diff --git a/Bootloader/CMakeLists.txt b/Bootloader/CMakeLists.txt
index ebe5ff4..704115d 100644
--- a/Bootloader/CMakeLists.txt
+++ b/Bootloader/CMakeLists.txt
@@ -20,11 +20,26 @@
 #| You _MUST_ clean the build directory if you change this value
 #|
 set( CHIP
-	"mk20dx128vlf5"    # McHCK    mk20dx128vlf5
-#	"mk20dx256vlh7"    # Kiibohd-dfu
+	"mk20dx128vlf5"    # McHCK       mk20dx128vlf5
+#	"mk20dx256vlh7"    # Kiibohd-dfu mk20dx256vlh7
 )
 
 
+
+###
+# Compiler Selection
+#
+
+#| *** EXPERIMENTAL ***
+#| Stick with gcc unless you know what you're doing
+#| Currently only arm is supported with clang
+set( COMPILER
+	"gcc"	# arm-none-eabi-gcc / avr-gcc - Default
+#	"clang" # arm-none-eabi
+	CACHE STRING "Compiler Type" )
+
+
+
 ###
 # Bootloader Configuration
 #
diff --git a/Bootloader/flash.c b/Bootloader/flash.c
index 9ae6dae..db2ef8f 100644
--- a/Bootloader/flash.c
+++ b/Bootloader/flash.c
@@ -68,7 +68,6 @@ int flash_erase_sector(uintptr_t addr)
 
 int flash_program_section(uintptr_t addr, size_t num_words)
 {
-	GPIOA_PSOR |= (1<<19);
         FTFL.fccob.program_section.fcmd = FTFL_FCMD_PROGRAM_SECTION;
         FTFL.fccob.program_section.addr = addr;
         FTFL.fccob.program_section.num_words = num_words;
diff --git a/Lib/mk20dx.c b/Lib/mk20dx.c
index 9b31949..d7a8cde 100644
--- a/Lib/mk20dx.c
+++ b/Lib/mk20dx.c
@@ -1,7 +1,7 @@
 /* Teensyduino Core Library
  * http://www.pjrc.com/teensy/
  * Copyright (c) 2013 PJRC.COM, LLC.
- * Modifications by Jacob Alexander 2014
+ * Modifications by Jacob Alexander 2014-2015
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the
@@ -29,6 +29,8 @@
  * SOFTWARE.
  */
 
+// ----- Includes -----
+
 // Local Includes
 #include "mk20dx.h"
 
@@ -246,7 +248,7 @@ void (* const gVectors[])() =
 	portd_isr,                                      // 59 Pin detect (Port D)
 	porte_isr,                                      // 60 Pin detect (Port E)
 	software_isr,                                   // 61 Software interrupt
-#elif defined(_mk20dx256_)
+#elif defined(_mk20dx256_) || defined(_mk20dx256vlh7_)
 	dma_ch0_isr,                                    // 16 DMA channel 0 transfer complete
 	dma_ch1_isr,                                    // 17 DMA channel 1 transfer complete
 	dma_ch2_isr,                                    // 18 DMA channel 2 transfer complete
@@ -404,7 +406,7 @@ const uint8_t flashconfigbytes[16] = {
 
 // ----- Functions -----
 
-#if defined(_mk20dx128vlf5_) && defined(_bootloader_) // Bootloader Section
+#if ( defined(_mk20dx128vlf5_) || defined(_mk20dx256vlh7_) ) && defined(_bootloader_) // Bootloader Section
 __attribute__((noreturn))
 static inline void jump_to_app( uintptr_t addr )
 {
@@ -453,18 +455,20 @@ void *memcpy( void *dst, const void *src, unsigned int len )
 __attribute__ ((section(".startup")))
 void ResetHandler()
 {
-	// Disable Watchdog
-	WDOG_UNLOCK = WDOG_UNLOCK_SEQ1;
-	WDOG_UNLOCK = WDOG_UNLOCK_SEQ2;
-	WDOG_STCTRLH = WDOG_STCTRLH_ALLOWUPDATE;
-
-#if defined(_mk20dx128vlf5_) && defined(_bootloader_) // Bootloader Section
+#if ( defined(_mk20dx128vlf5_) || defined(_mk20dx256vlh7_) ) && defined(_bootloader_) // Bootloader Section
 	extern uint32_t _app_rom;
 
 	// We treat _app_rom as pointer to directly read the stack
 	// pointer and check for valid app code.  This is no fool
 	// proof method, but it should help for the first flash.
-	if ( RCM_SRS0 & 0x40 || _app_rom == 0xffffffff ||
+	//
+	// Purposefully disabling the watchdog *after* the reset check this way
+	// if the chip goes into an odd state we'll reset to the bootloader (invalid firmware image)
+	// RCM_SRS0 & 0x20
+	//
+	// Also checking for ARM lock-up signal (invalid firmware image)
+	// RCM_SRS1 & 0x02
+	if ( RCM_SRS0 & 0x40 || RCM_SRS0 & 0x20 || RCM_SRS1 & 0x02 || _app_rom == 0xffffffff ||
 	  memcmp( (uint8_t*)&VBAT, sys_reset_to_loader_magic, sizeof(sys_reset_to_loader_magic) ) == 0 ) // Check for soft reload
 	{
 		memset( (uint8_t*)&VBAT, 0, sizeof(VBAT) );
@@ -476,6 +480,10 @@ void ResetHandler()
 		jump_to_app( addr );
 	}
 #endif
+	// Disable Watchdog
+	WDOG_UNLOCK = WDOG_UNLOCK_SEQ1;
+	WDOG_UNLOCK = WDOG_UNLOCK_SEQ2;
+	WDOG_STCTRLH = WDOG_STCTRLH_ALLOWUPDATE;
 
 	uint32_t *src = (uint32_t*)&_etext;
 	uint32_t *dest = (uint32_t*)&_sdata;
@@ -510,7 +518,7 @@ void ResetHandler()
 	dest = (uint32_t*)&_sbss;
 	while ( dest < (uint32_t*)&_ebss ) *dest++ = 0;
 
-// MCHCK
+// MCHCK / Kiibohd-dfu
 #if defined(_mk20dx128vlf5_)
 	// Default all interrupts to medium priority level
 	for ( unsigned int i = 0; i < NVIC_NUM_INTERRUPTS; i++ )
@@ -524,14 +532,12 @@ void ResetHandler()
 	// USB Clock and FLL select
 	SIM_SOPT2 = SIM_SOPT2_USBSRC | SIM_SOPT2_TRACECLKSEL;
 
-// Teensy 3.0 and 3.1
+// Teensy 3.0 and 3.1 and Kiibohd-dfu (mk20dx256vlh7)
 #else
-	unsigned int i;
-
 	SCB_VTOR = 0;	// use vector table in flash
 
 	// default all interrupts to medium priority level
-	for ( i = 0; i < NVIC_NUM_INTERRUPTS; i++ )
+	for ( unsigned int i = 0; i < NVIC_NUM_INTERRUPTS; i++ )
 	{
 		NVIC_SET_PRIORITY( i, 128 );
 	}