diff --git a/converter/adb_usb/matrix.c b/converter/adb_usb/matrix.c
index 6190c71a..8f6a0dc9 100644
--- a/converter/adb_usb/matrix.c
+++ b/converter/adb_usb/matrix.c
@@ -31,44 +31,18 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "host.h"
 
 
-#if (MATRIX_COLS > 16)
-#   error "MATRIX_COLS must not exceed 16"
-#endif
-#if (MATRIX_ROWS > 255)
-#   error "MATRIX_ROWS must not exceed 255"
-#endif
 
 
 static bool has_media_keys = false;
 static bool is_iso_layout = false;
-static bool is_modified = false;
 static report_mouse_t mouse_report = {};
 
 // matrix state buffer(1:on, 0:off)
-#if (MATRIX_COLS <= 8)
-static uint8_t matrix[MATRIX_ROWS];
-#else
-static uint16_t matrix[MATRIX_ROWS];
-#endif
+static matrix_row_t matrix[MATRIX_ROWS];
 
-#ifdef MATRIX_HAS_GHOST
-static bool matrix_has_ghost_in_row(uint8_t row);
-#endif
 static void register_key(uint8_t key);
 
 
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 void matrix_init(void)
 {
     // LED on
@@ -208,8 +182,6 @@ uint8_t matrix_scan(void)
     uint16_t codes;
     uint8_t key0, key1;
 
-    is_modified = false;
-
     codes = extra_key;
     extra_key = 0xFFFF;
 
@@ -328,93 +300,12 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-bool matrix_is_modified(void)
-{
-    return is_modified;
-}
-
 inline
-bool matrix_has_ghost(void)
-{
-#ifdef MATRIX_HAS_GHOST
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        if (matrix_has_ghost_in_row(i))
-            return true;
-    }
-#endif
-    return false;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
-inline
-#if (MATRIX_COLS <= 8)
-uint8_t matrix_get_row(uint8_t row)
-#else
-uint16_t matrix_get_row(uint8_t row)
-#endif
+matrix_row_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    if (!debug_matrix) return;
-#if (MATRIX_COLS <= 8)
-    print("r/c 01234567\n");
-#else
-    print("r/c 0123456789ABCDEF\n");
-#endif
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        phex(row); print(": ");
-#if (MATRIX_COLS <= 8)
-        pbin_reverse(matrix_get_row(row));
-#else
-        pbin_reverse16(matrix_get_row(row));
-#endif
-#ifdef MATRIX_HAS_GHOST
-        if (matrix_has_ghost_in_row(row)) {
-            print(" <ghost");
-        }
-#endif
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-#if (MATRIX_COLS <= 8)
-        count += bitpop(matrix[i]);
-#else
-        count += bitpop16(matrix[i]);
-#endif
-    }
-    return count;
-}
-
-#ifdef MATRIX_HAS_GHOST
-inline
-static bool matrix_has_ghost_in_row(uint8_t row)
-{
-    // no ghost exists in case less than 2 keys on
-    if (((matrix[row] - 1) & matrix[row]) == 0)
-        return false;
-
-    // ghost exists in case same state as other row
-    for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        if (i != row && (matrix[i] & matrix[row]) == matrix[row])
-            return true;
-    }
-    return false;
-}
-#endif
-
 inline
 static void register_key(uint8_t key)
 {
@@ -426,5 +317,4 @@ static void register_key(uint8_t key)
     } else {
         matrix[row] |=  (1<<col);
     }
-    is_modified = true;
 }
diff --git a/converter/ibm4704_usb/matrix.c b/converter/ibm4704_usb/matrix.c
index 8b9b518d..c02d9e50 100644
--- a/converter/ibm4704_usb/matrix.c
+++ b/converter/ibm4704_usb/matrix.c
@@ -52,18 +52,6 @@ static uint8_t matrix[MATRIX_ROWS];
 #define COL(code)      (code&0x07)
 
 
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 static void enable_break(void)
 {
     print("Enable break: ");
@@ -120,28 +108,12 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 inline
 uint8_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        xprintf("%02X: %08b\n", row, bitrev(matrix_get_row(row)));
-    }
-}
-
-
-
 inline
 static void matrix_make(uint8_t code)
 {
diff --git a/converter/m0110_usb/matrix.c b/converter/m0110_usb/matrix.c
index 9dcdc0d6..b216aba1 100644
--- a/converter/m0110_usb/matrix.c
+++ b/converter/m0110_usb/matrix.c
@@ -46,18 +46,6 @@ static uint8_t _matrix0[MATRIX_ROWS];
 static void register_key(uint8_t key);
 
 
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 void matrix_init(void)
 {
     m0110_init();
@@ -95,48 +83,12 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-bool matrix_is_modified(void)
-{
-    return is_modified;
-}
-
-inline
-bool matrix_has_ghost(void)
-{
-    return false;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 inline
 uint8_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        phex(row); print(": ");
-        pbin_reverse(matrix_get_row(row));
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop(matrix[i]);
-    }
-    return count;
-}
-
 inline
 static void register_key(uint8_t key)
 {
diff --git a/converter/news_usb/matrix.c b/converter/news_usb/matrix.c
index f0d5b586..c92a4888 100644
--- a/converter/news_usb/matrix.c
+++ b/converter/news_usb/matrix.c
@@ -47,20 +47,6 @@ static uint8_t matrix[MATRIX_ROWS];
 #define ROW(code)      ((code>>3)&0xF)
 #define COL(code)      (code&0x07)
 
-static bool is_modified = false;
-
-
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
 
 void matrix_init(void)
 {
@@ -74,8 +60,6 @@ void matrix_init(void)
 
 uint8_t matrix_scan(void)
 {
-    is_modified = false;
-
     uint8_t code;
     code = news_recv();
     if (code == 0) {
@@ -87,56 +71,18 @@ uint8_t matrix_scan(void)
         // break code
         if (matrix_is_on(ROW(code), COL(code))) {
             matrix[ROW(code)] &= ~(1<<COL(code));
-            is_modified = true;
         }
     } else {
         // make code
         if (!matrix_is_on(ROW(code), COL(code))) {
             matrix[ROW(code)] |=  (1<<COL(code));
-            is_modified = true;
         }
     }
     return code;
 }
 
-bool matrix_is_modified(void)
-{
-    return is_modified;
-}
-
-inline
-bool matrix_has_ghost(void)
-{
-    return false;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 inline
 uint8_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
-
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        phex(row); print(": ");
-        pbin_reverse(matrix_get_row(row));
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop(matrix[i]);
-    }
-    return count;
-}
diff --git a/converter/next_usb/matrix.c b/converter/next_usb/matrix.c
index 524d5784..18395a7e 100644
--- a/converter/next_usb/matrix.c
+++ b/converter/next_usb/matrix.c
@@ -66,20 +66,6 @@ static uint8_t matrix[MATRIX_ROWS];
 
 static bool is_modified = false;
 
-/* number of matrix rows */
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-/* number of matrix columns */
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 #ifndef NEXT_KBD_LED1_ON
 #define NEXT_KBD_LED1_ON
 #endif
@@ -227,19 +213,6 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-/* whether modified from previous scan. used after matrix_scan. */
-bool matrix_is_modified()
-{
-    return is_modified;
-}
-
-/* whether a switch is on */
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 /* matrix state on row */
 inline
 uint8_t matrix_get_row(uint8_t row)
@@ -247,11 +220,6 @@ uint8_t matrix_get_row(uint8_t row)
     return matrix[row];
 }
 
-/* print matrix for debug */
-void matrix_print(void)
-{
-}
-
 inline
 static void matrix_make(uint8_t code)
 {
diff --git a/converter/pc98_usb/matrix.c b/converter/pc98_usb/matrix.c
index 8833e0a8..19cfb0c0 100644
--- a/converter/pc98_usb/matrix.c
+++ b/converter/pc98_usb/matrix.c
@@ -46,20 +46,6 @@ static uint8_t matrix[MATRIX_ROWS];
 #define ROW(code)      ((code>>3)&0xF)
 #define COL(code)      (code&0x07)
 
-static bool is_modified = false;
-
-
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
 
 static void pc98_inhibit_repeat(void)
 {
@@ -128,8 +114,6 @@ void matrix_init(void)
 
 uint8_t matrix_scan(void)
 {
-    is_modified = false;
-
     uint16_t code;
     PC98_RDY_PORT |= (1<<PC98_RDY_BIT);
     _delay_us(30);
@@ -156,56 +140,18 @@ if (code == 0x60) {
         // break code
         if (matrix_is_on(ROW(code), COL(code))) {
             matrix[ROW(code)] &= ~(1<<COL(code));
-            is_modified = true;
         }
     } else {
         // make code
         if (!matrix_is_on(ROW(code), COL(code))) {
             matrix[ROW(code)] |=  (1<<COL(code));
-            is_modified = true;
         }
     }
     return code;
 }
 
-bool matrix_is_modified(void)
-{
-    return is_modified;
-}
-
-inline
-bool matrix_has_ghost(void)
-{
-    return false;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 inline
 uint8_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
-
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        phex(row); print(": ");
-        pbin_reverse(matrix_get_row(row));
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop(matrix[i]);
-    }
-    return count;
-}
diff --git a/converter/sun_usb/matrix.c b/converter/sun_usb/matrix.c
index 3126bd33..c2b38ae0 100644
--- a/converter/sun_usb/matrix.c
+++ b/converter/sun_usb/matrix.c
@@ -24,6 +24,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "matrix.h"
 #include "debug.h"
 #include "protocol/serial.h"
+#include "led.h"
+#include "host.h"
 
 
 /*
@@ -46,20 +48,6 @@ static uint8_t matrix[MATRIX_ROWS];
 #define ROW(code)      ((code>>3)&0xF)
 #define COL(code)      (code&0x07)
 
-static bool is_modified = false;
-
-
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
 
 void matrix_init(void)
 {
@@ -92,8 +80,6 @@ void matrix_init(void)
 
 uint8_t matrix_scan(void)
 {
-    is_modified = false;
-
     uint8_t code;
     code = serial_recv();
     if (!code) return 0;
@@ -131,56 +117,18 @@ uint8_t matrix_scan(void)
         // break code
         if (matrix_is_on(ROW(code), COL(code))) {
             matrix[ROW(code)] &= ~(1<<COL(code));
-            is_modified = true;
         }
     } else {
         // make code
         if (!matrix_is_on(ROW(code), COL(code))) {
             matrix[ROW(code)] |=  (1<<COL(code));
-            is_modified = true;
         }
     }
     return code;
 }
 
-bool matrix_is_modified(void)
-{
-    return is_modified;
-}
-
-inline
-bool matrix_has_ghost(void)
-{
-    return false;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 inline
 uint8_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
-
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        phex(row); print(": ");
-        pbin_reverse(matrix_get_row(row));
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop(matrix[i]);
-    }
-    return count;
-}
diff --git a/converter/terminal_usb/matrix.c b/converter/terminal_usb/matrix.c
index 36901536..5d03e547 100644
--- a/converter/terminal_usb/matrix.c
+++ b/converter/terminal_usb/matrix.c
@@ -28,9 +28,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 static void matrix_make(uint8_t code);
 static void matrix_break(uint8_t code);
-#ifdef MATRIX_HAS_GHOST
-static bool matrix_has_ghost_in_row(uint8_t row);
-#endif
 
 
 /*
@@ -49,20 +46,6 @@ static uint8_t matrix[MATRIX_ROWS];
 #define ROW(code)      (code>>3)
 #define COL(code)      (code&0x07)
 
-static bool is_modified = false;
-
-
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
 
 void matrix_init(void)
 {
@@ -93,8 +76,6 @@ uint8_t matrix_scan(void)
         F0,
     } state = RESET;
 
-    is_modified = false;
-
     uint8_t code;
     if ((code = ps2_host_recv())) {
         debug("r"); debug_hex(code); debug(" ");
@@ -172,83 +153,17 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-bool matrix_is_modified(void)
-{
-    return is_modified;
-}
-
-inline
-bool matrix_has_ghost(void)
-{
-#ifdef MATRIX_HAS_GHOST
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        if (matrix_has_ghost_in_row(i))
-            return true;
-    }
-#endif
-    return false;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 inline
 uint8_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        phex(row); print(": ");
-        pbin_reverse(matrix_get_row(row));
-#ifdef MATRIX_HAS_GHOST
-        if (matrix_has_ghost_in_row(row)) {
-            print(" <ghost");
-        }
-#endif
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop(matrix[i]);
-    }
-    return count;
-}
-
-#ifdef MATRIX_HAS_GHOST
-inline
-static bool matrix_has_ghost_in_row(uint8_t row)
-{
-    // no ghost exists in case less than 2 keys on
-    if (((matrix[row] - 1) & matrix[row]) == 0)
-        return false;
-
-    // ghost exists in case same state as other row
-    for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        if (i != row && (matrix[i] & matrix[row]) == matrix[row])
-            return true;
-    }
-    return false;
-}
-#endif
-
-
 inline
 static void matrix_make(uint8_t code)
 {
     if (!matrix_is_on(ROW(code), COL(code))) {
         matrix[ROW(code)] |= 1<<COL(code);
-        is_modified = true;
     }
 }
 
@@ -257,6 +172,5 @@ static void matrix_break(uint8_t code)
 {
     if (matrix_is_on(ROW(code), COL(code))) {
         matrix[ROW(code)] &= ~(1<<COL(code));
-        is_modified = true;
     }
 }
diff --git a/converter/x68k_usb/matrix.c b/converter/x68k_usb/matrix.c
index 2d5a1e11..9dff7ba6 100644
--- a/converter/x68k_usb/matrix.c
+++ b/converter/x68k_usb/matrix.c
@@ -50,18 +50,6 @@ static uint8_t matrix[MATRIX_ROWS];
 static bool is_modified = false;
 
 
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 void matrix_init(void)
 {
     serial_init();
@@ -99,44 +87,8 @@ uint8_t matrix_scan(void)
     return code;
 }
 
-bool matrix_is_modified(void)
-{
-    return is_modified;
-}
-
-inline
-bool matrix_has_ghost(void)
-{
-    return false;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 inline
 uint8_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
-
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        phex(row); print(": ");
-        pbin_reverse(matrix_get_row(row));
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop(matrix[i]);
-    }
-    return count;
-}
diff --git a/converter/xt_usb/matrix.c b/converter/xt_usb/matrix.c
index de9706a6..51742dd2 100644
--- a/converter/xt_usb/matrix.c
+++ b/converter/xt_usb/matrix.c
@@ -28,9 +28,6 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 
 static void matrix_make(uint8_t code);
 static void matrix_break(uint8_t code);
-#ifdef MATRIX_HAS_GHOST
-static bool matrix_has_ghost_in_row(uint8_t row);
-#endif
 
 static uint8_t matrix[MATRIX_ROWS];
 #define ROW(code)      (code>>3)
@@ -40,20 +37,6 @@ static uint8_t matrix[MATRIX_ROWS];
 #define PRINT_SCREEN   (0x7C)
 #define PAUSE          (0x7D)
 
-static bool is_modified = false;
-
-
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
 
 void matrix_init(void)
 {
@@ -131,8 +114,6 @@ uint8_t matrix_scan(void)
     } state = INIT;
 
 
-    is_modified = false;
-
     // 'pseudo break code' hack
     if (matrix_is_on(ROW(PAUSE), COL(PAUSE))) {
         matrix_break(PAUSE);
@@ -236,83 +217,17 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-bool matrix_is_modified(void)
-{
-    return is_modified;
-}
-
-inline
-bool matrix_has_ghost(void)
-{
-#ifdef MATRIX_HAS_GHOST
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        if (matrix_has_ghost_in_row(i))
-            return true;
-    }
-#endif
-    return false;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 inline
 uint8_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        phex(row); print(": ");
-        pbin_reverse(matrix_get_row(row));
-#ifdef MATRIX_HAS_GHOST
-        if (matrix_has_ghost_in_row(row)) {
-            print(" <ghost");
-        }
-#endif
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop(matrix[i]);
-    }
-    return count;
-}
-
-#ifdef MATRIX_HAS_GHOST
-inline
-static bool matrix_has_ghost_in_row(uint8_t row)
-{
-    // no ghost exists in case less than 2 keys on
-    if (((matrix[row] - 1) & matrix[row]) == 0)
-        return false;
-
-    // ghost exists in case same state as other row
-    for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        if (i != row && (matrix[i] & matrix[row]) == matrix[row])
-            return true;
-    }
-    return false;
-}
-#endif
-
-
 inline
 static void matrix_make(uint8_t code)
 {
     if (!matrix_is_on(ROW(code), COL(code))) {
         matrix[ROW(code)] |= 1<<COL(code);
-        is_modified = true;
     }
 }
 
@@ -321,7 +236,6 @@ static void matrix_break(uint8_t code)
 {
     if (matrix_is_on(ROW(code), COL(code))) {
         matrix[ROW(code)] &= ~(1<<COL(code));
-        is_modified = true;
     }
 }
 
diff --git a/keyboard/alps64/matrix.c b/keyboard/alps64/matrix.c
index 5638d7f6..109bcf2c 100644
--- a/keyboard/alps64/matrix.c
+++ b/keyboard/alps64/matrix.c
@@ -43,18 +43,6 @@ static void unselect_rows(void);
 static void select_row(uint8_t row);
 
 
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 #define LED_ON()    do { DDRC |= (1<<5); PORTC |= (1<<5); } while (0)
 #define LED_OFF()   do { DDRC &= ~(1<<5); PORTC &= ~(1<<5); } while (0)
 #define LED_TGL()   do { DDRC |= (1<<5); PINC |= (1<<5); } while (0)
@@ -107,28 +95,12 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & ((matrix_row_t)1<<col));
-}
-
 inline
 matrix_row_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    print("\nr/c 0123456789ABCDEF\n");
-    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
-        phex(row); print(": ");
-        pbin_reverse16(matrix_get_row(row));
-        print("\n");
-    }
-}
-
 /* Column pin configuration
  * col: 0   1   2   3   4   5   6   7
  * pin: B0  B1  B2  B3  B4  B5  B6  B7
diff --git a/keyboard/gh60/matrix.c b/keyboard/gh60/matrix.c
index a6121515..5a56cee0 100644
--- a/keyboard/gh60/matrix.c
+++ b/keyboard/gh60/matrix.c
@@ -43,18 +43,6 @@ static void unselect_rows(void);
 static void select_row(uint8_t row);
 
 
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 void matrix_init(void)
 {
     // initialize row and col
@@ -97,43 +85,12 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-bool matrix_is_modified(void)
-{
-    if (debouncing) return false;
-    return true;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & ((matrix_row_t)1<<col));
-}
-
 inline
 matrix_row_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    print("\nr/c 0123456789ABCDEF\n");
-    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
-        phex(row); print(": ");
-        pbin_reverse16(matrix_get_row(row));
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop16(matrix[i]);
-    }
-    return count;
-}
-
 /* Column pin configuration
  * col: 0   1   2   3   4   5   6   7   8   9   10  11  12  13
  * pin: F0  F1  E6  C7  C6  B6  D4  B1  B0  B5  B4  D7  D6  B3  (Rev.A)
diff --git a/keyboard/hbkb/matrix.c b/keyboard/hbkb/matrix.c
index ee32312d..86c18b4b 100644
--- a/keyboard/hbkb/matrix.c
+++ b/keyboard/hbkb/matrix.c
@@ -41,26 +41,11 @@ static uint8_t debouncing = DEBOUNCE;
 static matrix_row_t matrix[MATRIX_ROWS];
 static matrix_row_t matrix_debouncing[MATRIX_ROWS];
 
-#ifdef MATRIX_HAS_GHOST
-static bool matrix_has_ghost_in_row(uint8_t row);
-#endif
 static matrix_row_t read_cols(void);
 static void unselect_rows(void);
 static void select_row(uint8_t row);
 
 
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 void matrix_init(void)
 {
     // JTAG disable for PORT F. write JTD bit twice within four cycles.
@@ -110,56 +95,12 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-bool matrix_is_modified(void)
-{
-    if (debouncing) return false;
-    return true;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & ((matrix_row_t)1<<col));
-}
-
 inline
 matrix_row_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        phex(row); print(": ");
-        pbin_reverse(matrix_get_row(row));
-#ifdef MATRIX_HAS_GHOST
-        if (matrix_has_ghost_in_row(row)) {
-            print(" <ghost");
-        }
-#endif
-        print("\n");
-    }
-}
-
-#ifdef MATRIX_HAS_GHOST
-inline
-static bool matrix_has_ghost_in_row(uint8_t row)
-{
-    // no ghost exists in case less than 2 keys on
-    if (((matrix[row] - 1) & matrix[row]) == 0)
-        return false;
-
-    // ghost exists in case same state as other row
-    for (uint8_t i=0; i < MATRIX_ROWS; i++) {
-        if (i != row && (matrix[i] & matrix[row]))
-            return true;
-    }
-    return false;
-}
-#endif
-
 inline
 static matrix_row_t read_cols(void)
 {
diff --git a/keyboard/hhkb/matrix.c b/keyboard/hhkb/matrix.c
index 14fae0b8..08721fc5 100644
--- a/keyboard/hhkb/matrix.c
+++ b/keyboard/hhkb/matrix.c
@@ -43,18 +43,6 @@ static matrix_row_t _matrix0[MATRIX_ROWS];
 static matrix_row_t _matrix1[MATRIX_ROWS];
 
 
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 void matrix_init(void)
 {
 #ifdef DEBUG
@@ -153,41 +141,12 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-bool matrix_is_modified(void)
-{
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        if (matrix[i] != matrix_prev[i])
-            return true;
-    }
-    return false;
-}
-
-inline
-bool matrix_has_ghost(void)
-{
-    return false;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & (1<<col));
-}
-
 inline
 matrix_row_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    print("\nr/c 01234567\n");
-    for (uint8_t row = 0; row < matrix_rows(); row++) {
-        xprintf("%02X: %08b\n", row, bitrev(matrix_get_row(row)));
-    }
-}
-
 void matrix_power_up(void) {
     KEY_POWER_ON();
 }
diff --git a/keyboard/onekey/matrix.c b/keyboard/onekey/matrix.c
index 29df8683..d78e47ec 100644
--- a/keyboard/onekey/matrix.c
+++ b/keyboard/onekey/matrix.c
@@ -43,18 +43,6 @@ static void unselect_rows(void);
 static void select_row(uint8_t row);
 
 
-inline
-uint8_t matrix_rows(void)
-{
-    return MATRIX_ROWS;
-}
-
-inline
-uint8_t matrix_cols(void)
-{
-    return MATRIX_COLS;
-}
-
 void matrix_init(void)
 {
     debug_enable = true;
@@ -100,43 +88,12 @@ uint8_t matrix_scan(void)
     return 1;
 }
 
-bool matrix_is_modified(void)
-{
-    if (debouncing) return false;
-    return true;
-}
-
-inline
-bool matrix_is_on(uint8_t row, uint8_t col)
-{
-    return (matrix[row] & ((matrix_row_t)1<<col));
-}
-
 inline
 matrix_row_t matrix_get_row(uint8_t row)
 {
     return matrix[row];
 }
 
-void matrix_print(void)
-{
-    print("\nr/c 0123456789ABCDEF\n");
-    for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
-        phex(row); print(": ");
-        pbin_reverse16(matrix_get_row(row));
-        print("\n");
-    }
-}
-
-uint8_t matrix_key_count(void)
-{
-    uint8_t count = 0;
-    for (uint8_t i = 0; i < MATRIX_ROWS; i++) {
-        count += bitpop16(matrix[i]);
-    }
-    return count;
-}
-
 /* Column pin configuration
  * col: 0
  * pin: B0
diff --git a/tmk_core/common/matrix.c b/tmk_core/common/matrix.c
index 9694bd1a..9939307a 100644
--- a/tmk_core/common/matrix.c
+++ b/tmk_core/common/matrix.c
@@ -33,7 +33,6 @@ uint8_t matrix_cols(void)
 __attribute__ ((weak))
 void matrix_clear(void)
 {
-    matrix_init();
 }
 
 __attribute__ ((weak))
@@ -55,23 +54,22 @@ void matrix_print(void)
 #elif (MATRIX_COLS <= 32)
     print("r/c 0123456789ABCDEF0123456789ABCDEF\n");
 #endif
+
     for (uint8_t row = 0; row < MATRIX_ROWS; row++) {
-        xprintf("%02X:", row);
 
 #if (MATRIX_COLS <= 8)
-        print_bin_reverse8(matrix_get_row(row));
+        xprintf("%02X: %08b%s\n", row, bitrev(matrix_get_row(row)),
 #elif (MATRIX_COLS <= 16)
-        print_bin_reverse16(matrix_get_row(row));
+        xprintf("%02X: %016b%s\n", row, bitrev16(matrix_get_row(row)),
 #elif (MATRIX_COLS <= 32)
-        print_bin_reverse32(matrix_get_row(row));
+        xprintf("%02X: %032b%s\n", row, bitrev32(matrix_get_row(row)),
 #endif
-
 #ifdef MATRIX_HAS_GHOST
-        if (matrix_has_ghost_in_row(row)) {
-            print(" <ghost");
-        }
+        matrix_has_ghost_in_row(row) ?  " <ghost" : ""
+#else
+        ""
 #endif
-        print("\n");
+        );
     }
 }
 
diff --git a/tmk_core/common/matrix.h b/tmk_core/common/matrix.h
index e913ee7a..bf866477 100644
--- a/tmk_core/common/matrix.h
+++ b/tmk_core/common/matrix.h
@@ -32,6 +32,10 @@ typedef  uint32_t   matrix_row_t;
 #error "MATRIX_COLS: invalid value"
 #endif
 
+#if (MATRIX_ROWS > 255)
+#error "MATRIX_ROWS must not exceed 255"
+#endif
+
 #define MATRIX_IS_ON(row, col)  (matrix_get_row(row) && (1<<col))