Fixup bootloaders. (#16256)

keyboards/jm60/jm60.c

@@ -20,3 +20,8 @@ along with this program.  If not, see <http://www.gnu.org/licenses/>.
 void board_init(void) {
 	AFIO->MAPR |= AFIO_MAPR_SWJ_CFG_JTAGDISABLE;
 }
+
+void bootloader_jump(void) {
+    // This board doesn't use the "standard" stm32duino bootloader. There's no information on how to jump to the custom bootloader, so all we can do here is reset.
+    NVIC_SystemReset();
+}