Reboot to bootloader

This implements rebooting to bootloader via os.reset(True). To do that we modify the bootloader so that it checks for a special file named .mscmode and if it's there it removes it and runs msc(). On Python side we declare .mscmode as a restricted file and create it before rebooting if needed.

This also improves update-bootloader.bin building because I didn't get a debugger :D It now automatically uses the latest bootloader, so you can grab update-bootloader.bin.

bootloader/main.c

@@ -2,6 +2,7 @@
 #include "card10-version.h"
 
 #include "card10.h"
+#include "card10-platform.h"
 #include "led.h"
 #include "pb.h"
 #include "pmic.h"
@@ -29,6 +30,11 @@
 #define PARTITION_START (0x10000000 + 64 * 1024)
 #define PARTITION_END (0x10000000 + 1024 * 1024 - 1)
 
+struct bootloader_version __attribute__((section(".bootloader_version"))) __bootloader_version = {
+	.magic = BOOTLOADER_MAGIC,
+	.version = BOOTLOADER_VERSION,
+};
+
 DIR dir;
 FATFS FatFs;
 
@@ -68,6 +74,18 @@ int mount(void)
 	return 0;
 }
 
+int get_msc_flag(void)
+{
+	// We use the API call memory to store a magic value there.
+	uint32_t* flag = API_CALL_MEM_ADDRESS;
+	if (*flag == MSC_MAGIC) {
+		*flag = 0;
+		return 1;
+	} else {
+		return 0;
+	}
+}
+
 int check_integrity(void)
 {
 	FIL file;
@@ -242,8 +260,8 @@ int main(void)
 
 	bootloader_display_init();
 
-	// If the button is pressed, we go into MSC mode.
-	if (PB_Get(3)) {
+	// If the button is pressed or a flag in memory is detected, we go into MSC mode.
+	if (PB_Get(3) || get_msc_flag()) {
 		msc();
 	}