diff --git a/startup_stm32f042x6.s b/startup_stm32f042x6.s
--- a/startup_stm32f042x6.s
+++ b/startup_stm32f042x6.s
@@ -64,6 +64,17 @@ defined in linker script */
   .weak Reset_Handler
   .type Reset_Handler, %function
 Reset_Handler:
+
+  /* Bootloader jumping */
+  ldr r0, =0x200017F0 /* address of magic token, is addr within memory range? */
+  ldr r1, =0xDEADBEEF /* magical beef token */
+  ldr r2, [r0, #0] /* load data from magic address */
+  str r0, [r0, #0] /* zero data at magic address so we don't bootloop */ 
+  cmp r2, r1 /* compare data at magic address to magic token */
+  beq Reboot_Loader /* jump to bootloader if token match */
+  /* End bootloader jumping */
+
+
   ldr   r0, =_estack
   mov   sp, r0          /* set stack pointer */
 
@@ -71,6 +82,19 @@ Reset_Handler:
   movs r1, #0
   b LoopCopyDataInit
 
+/* Boot into bootloader */
+Reboot_Loader:
+  ldr r0, =0x1FFFF6A6 /* Address of bootloader on f042 from CD00167594 pg 15 table 3 */
+  /* This replaces ldr sp, [r0, #0] which doesn't work on m0 */
+  // Set stack pointer
+  ldr r1, [r0, #0]
+  mov sp, r1
+
+  // Branch to bootloader
+  ldr r0, [r0, #4]
+  bx r0
+
+
 CopyDataInit:
   ldr r3, =_sidata
   ldr r3, [r3, r1]