diff --git a/keyboard/kimera/kimera.c b/keyboard/kimera/kimera.c
index c4c42f8d..7082ab42 100644
--- a/keyboard/kimera/kimera.c
+++ b/keyboard/kimera/kimera.c
@@ -86,6 +86,17 @@ static matrix_row_t col_left_mask;
 static uint8_t data[EXP_COUNT][EXP_PORT_COUNT];
 static uint8_t exp_status = 0;
 
+static uint8_t read_matrix_mapping(void);
+static void write_matrix_mapping(void);
+static void expander_init(uint8_t exp);
+static uint8_t expander_write(uint8_t exp, uint8_t command, uint8_t *data);
+static uint8_t expander_read(uint8_t exp, uint8_t command, uint8_t *data);
+static uint8_t expander_write_output(uint8_t exp, uint8_t *data);
+static uint8_t expander_write_inversion(uint8_t exp, uint8_t *data);
+static uint8_t expander_write_config(uint8_t exp, uint8_t *data);
+static uint8_t expander_read_input(uint8_t exp, uint8_t *data);
+static void init_data(uint8_t value);
+
 void kimera_init(void)
 {
     /* read config */
@@ -130,7 +141,7 @@ uint8_t read_matrix_mapping(void)
 #ifdef TWO_HEADED_KIMERA
     row_left_count = (rows + 1) / 2;
     col_left_count = (cols + 1) / 2;
-    col_left_mask = (1 << row_left_count) - 1;
+    col_left_mask = (1 << col_left_count) - 1;
 #endif
 
     /* read row mapping */
@@ -200,30 +211,68 @@ void kimera_scan(void)
     }
 }
 
+#define CHANGE_COMBINING 1
+
 inline
 uint8_t kimera_matrix_rows(void)
 {
+#if CHANGE_COMBINING
+#ifndef TWO_HEADED_KIMERA
     return row_count;
+#else
+    return row_left_count;
+#endif
+#else
+    return row_count;
+#endif
 }
 
 inline
 uint8_t kimera_matrix_cols(void)
 {
+#if CHANGE_COMBINING
+    return col_count;
+#else
 #ifndef TWO_HEADED_KIMERA
     return col_count;
 #else
     return col_left_count;
 #endif
+#endif
 }
 
-matrix_row_t kimera_read_cols(uint8_t row)
+void kimera_read_cols(void)
 {
-    init_data(0xFF);
-
     /* read all input registers */
+    init_data(0xFF);
     for (uint8_t exp = 0; exp < EXP_COUNT; exp++) {
         expander_read_input(exp, data[exp]);
     }
+}
+
+uint8_t kimera_get_col(uint8_t row, uint8_t col)
+{
+#if CHANGE_COMBINING
+#else
+#ifdef TWO_HEADED_KIMERA
+    if (row >= row_left_count) {
+        col += col_left_count;
+    }
+#endif
+#endif
+
+    uint8_t px = col_mapping[col];
+    if (px != UNCONFIGURED) {
+        if (!(data[PX_TO_EXP(px)][PX_TO_PORT(px)] & (1 << PX_TO_PIN(px)))) {
+            return 1;
+        }
+    }
+    return 0;
+}
+
+matrix_row_t kimera_read_row(uint8_t row)
+{
+    kimera_read_cols();
 
     /* make cols */
     matrix_row_t cols = 0;
@@ -236,6 +285,8 @@ matrix_row_t kimera_read_cols(uint8_t row)
         }
     }
 
+#if CHANGE_COMBINING
+#else
 #ifdef TWO_HEADED_KIMERA
     if (row < row_left_count) {
         cols &= col_left_mask;
@@ -243,6 +294,7 @@ matrix_row_t kimera_read_cols(uint8_t row)
     else {
         cols >>= col_left_count;
     }
+#endif
 #endif
 
     return cols;
@@ -267,6 +319,13 @@ void kimera_select_row(uint8_t row)
         data[exp][PX_TO_PORT(px)] &= ~(1 << PX_TO_PIN(px));
         expander_write_config(exp, data[exp]);
     }
+#if CHANGE_COMBINING
+#ifdef TWO_HEADED_KIMERA
+    if (row < row_left_count) {
+        kimera_select_row(row + row_left_count);
+    }
+#endif
+#endif
 }
 
 void expander_init(uint8_t exp)
@@ -349,6 +408,7 @@ uint8_t expander_write_config(uint8_t exp, uint8_t *data)
 {
     return expander_write(exp, EXP_COMM_CONFIG_0, data);
 }
+
 inline
 uint8_t expander_read_input(uint8_t exp, uint8_t *data)
 {
diff --git a/keyboard/kimera/kimera.h b/keyboard/kimera/kimera.h
index 24d3c132..7769efe3 100644
--- a/keyboard/kimera/kimera.h
+++ b/keyboard/kimera/kimera.h
@@ -156,22 +156,13 @@ const uint16_t PROGMEM dummy[] = {
 /* Functions */
 
 void kimera_init(void);
-void wdt_init(void);
-uint8_t read_matrix_mapping(void);
-void write_matrix_mapping(void);
 void kimera_scan(void);
 uint8_t kimera_matrix_rows(void);
 uint8_t kimera_matrix_cols(void);
-matrix_row_t kimera_read_cols(uint8_t row);
+void kimera_read_cols(void);
+uint8_t kimera_get_col(uint8_t row, uint8_t col);
+matrix_row_t kimera_read_row(uint8_t row);
 void kimera_unselect_rows(void);
 void kimera_select_row(uint8_t row);
-void expander_init(uint8_t exp);
-uint8_t expander_write(uint8_t exp, uint8_t command, uint8_t *data);
-uint8_t expander_read(uint8_t exp, uint8_t command, uint8_t *data);
-uint8_t expander_write_output(uint8_t exp, uint8_t *data);
-uint8_t expander_write_inversion(uint8_t exp, uint8_t *data);
-uint8_t expander_write_config(uint8_t exp, uint8_t *data);
-uint8_t expander_read_input(uint8_t exp, uint8_t *data);
-void init_data(uint8_t value);
 
 #endif
diff --git a/keyboard/kimera/matrix.c b/keyboard/kimera/matrix.c
index bc7b9387..83d2975b 100644
--- a/keyboard/kimera/matrix.c
+++ b/keyboard/kimera/matrix.c
@@ -28,16 +28,29 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #include "matrix.h"
 #include "kimera.h"
 #include "keymap_in_eeprom.h"
+#include "timer.h"
 
 
 #ifndef DEBOUNCE
 #   define DEBOUNCE	5
 #endif
-static uint8_t debouncing = DEBOUNCE;
 
 /* matrix state(1:on, 0:off) */
 static matrix_row_t matrix[MATRIX_ROWS];
+
+#define IMPROVED_DEBOUNCE 1
+
+#if IMPROVED_DEBOUNCE
+#define DEBOUNCE_MASK ((1 << DEBOUNCE) - 1)
+static uint8_t matrix_current_row;
+static uint16_t matrix_row_timestamp[MATRIX_ROWS];
+static uint8_t matrix_debouncing[MATRIX_ROWS][MATRIX_COLS];
+#else
+static uint8_t debouncing = DEBOUNCE;
 static matrix_row_t matrix_debouncing[MATRIX_ROWS];
+#endif
+
+static uint16_t kimera_scan_timestamp;
 
 inline
 uint8_t matrix_rows(void)
@@ -58,15 +71,27 @@ void matrix_init(void)
     MCUCR = (1<<JTD);
 
     kimera_init();
+    kimera_scan_timestamp = timer_read();
 
     // initialize row and col
     kimera_unselect_rows();
 
     // initialize matrix state: all keys off
+#if IMPROVED_DEBOUNCE
+    for (uint8_t i = 0; i < matrix_rows(); i++) {
+        matrix[i] = 0;
+        matrix_current_row = 0;
+        matrix_row_timestamp[i] = timer_read();
+        for (uint8_t j = 0; j < matrix_cols(); j++) {
+            matrix_debouncing[i][j] = 0;
+        }
+    }
+#else
     for (uint8_t i=0; i < matrix_rows(); i++) {
         matrix[i] = 0;
         matrix_debouncing[i] = 0;
     }
+#endif
 
     PORTD &= ~(1<<PD4);
 
@@ -74,12 +99,123 @@ void matrix_init(void)
 
 uint8_t matrix_scan(void)
 {
-    kimera_scan();
 
+    /* xprintf("Row: %d, %u\n", matrix_current_row, timer_read()); */
+
+    if (timer_elapsed(kimera_scan_timestamp) >= 1000) {
+        xprintf("Scan, %u\n", kimera_scan_timestamp);
+        kimera_scan_timestamp = timer_read();
+        kimera_scan();
+    }
+
+#if IMPROVED_DEBOUNCE
+    uint16_t elapsed = timer_elapsed(matrix_row_timestamp[matrix_current_row]);
+    if (elapsed >= 1) {
+        matrix_row_timestamp[matrix_current_row] = timer_read();
+        kimera_select_row(matrix_current_row);
+        _delay_us(30);
+        kimera_read_cols();
+        for (uint8_t i = 0; i < matrix_cols(); i++) {
+            uint8_t *debounce = &matrix_debouncing[matrix_current_row][i];
+            uint8_t col = kimera_get_col(matrix_current_row, i);
+            uint8_t count = elapsed;
+            do {
+                *debounce <<= 1;
+                *debounce |= col;
+            } while (--count);
+            matrix_row_t *row = &matrix[matrix_current_row];
+            matrix_row_t mask = ((matrix_row_t)1 << i);
+            switch (*debounce & DEBOUNCE_MASK) {
+                case DEBOUNCE_MASK:
+#if DEBOUNCE > 1
+                case (DEBOUNCE_MASK >> 1):
+#if DEBOUNCE > 2
+                case (DEBOUNCE_MASK >> 2):
+#if DEBOUNCE > 3
+                case (DEBOUNCE_MASK >> 3):
+#if DEBOUNCE > 4
+                case (DEBOUNCE_MASK >> 4):
+#if DEBOUNCE > 5
+                case (DEBOUNCE_MASK >> 5):
+#if DEBOUNCE > 6
+                case (DEBOUNCE_MASK >> 6):
+#if DEBOUNCE > 7
+                case (DEBOUNCE_MASK >> 7):
+#if DEBOUNCE > 8
+                case (DEBOUNCE_MASK >> 8):
+#if DEBOUNCE > 9
+                case (DEBOUNCE_MASK >> 9):
+#if DEBOUNCE > 10
+                case (DEBOUNCE_MASK >> 10):
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+                    if ((*row & mask) == 0) {
+                        *row |= mask;
+                    }
+                    break;
+#if DEBOUNCE > 1
+                case ((DEBOUNCE_MASK << 1) & DEBOUNCE_MASK):
+#if DEBOUNCE > 2
+                case ((DEBOUNCE_MASK << 2) & DEBOUNCE_MASK):
+#if DEBOUNCE > 3
+                case ((DEBOUNCE_MASK << 3) & DEBOUNCE_MASK):
+#if DEBOUNCE > 4
+                case ((DEBOUNCE_MASK << 4) & DEBOUNCE_MASK):
+#if DEBOUNCE > 5
+                case ((DEBOUNCE_MASK << 5) & DEBOUNCE_MASK):
+#if DEBOUNCE > 6
+                case ((DEBOUNCE_MASK << 6) & DEBOUNCE_MASK):
+#if DEBOUNCE > 7
+                case ((DEBOUNCE_MASK << 7) & DEBOUNCE_MASK):
+#if DEBOUNCE > 8
+                case ((DEBOUNCE_MASK << 8) & DEBOUNCE_MASK):
+#if DEBOUNCE > 9
+                case ((DEBOUNCE_MASK << 9) & DEBOUNCE_MASK):
+#if DEBOUNCE > 10
+                case ((DEBOUNCE_MASK << 10) & DEBOUNCE_MASK):
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+#endif
+                    break;
+                case 0:
+                    if ((*row & mask) != 0) {
+                        *row &= ~mask;
+                    }
+                    break;
+                default:
+                    debug("bounce!: ");
+                    debug_bin8(*debounce & DEBOUNCE_MASK);
+                    debug("\n");
+                    break;
+            }
+        }
+        kimera_unselect_rows();
+    }
+
+    matrix_current_row++;
+    if (matrix_current_row >= matrix_rows()) {
+        matrix_current_row = 0;
+    }
+#else
     for (uint8_t i = 0; i < matrix_rows(); i++) {
         kimera_select_row(i);
         _delay_us(30);  // without this wait read unstable value.
-        matrix_row_t cols = kimera_read_cols(i);
+        matrix_row_t cols = kimera_read_row(i);
         if (matrix_debouncing[i] != cols) {
             matrix_debouncing[i] = cols;
             if (debouncing) {
@@ -99,15 +235,19 @@ uint8_t matrix_scan(void)
             }
         }
     }
+#endif
 
     return 1;
 }
 
+#if IMPROVED_DEBOUNCE
+#else
 bool matrix_is_modified(void)
 {
     if (debouncing) return false;
     return true;
 }
+#endif
 
 inline
 bool matrix_is_on(uint8_t row, uint8_t col)