You need a hardware programmer to fix this. e.g. JLink (clones work OK but not the small STM32 Jlink as the Reset pin is missing)
Programmers like this work OK
Unfortunately I checked eBay spain can I can't find any local
JLink Edu is also OK.
Download the JLink software from Segger.com
- Remove the battery
- Removed 4 screws at back of radio
- Remove volume knob
- Unscrew antenna and volume nut rings
- Carefully slide and open the radio.
The front is connected via a ribbon cable for the display / keyboard and also 2 wires for the speaker.
Probably unsolder the speaker wires and disconnect the ribbon cable from the main PCB, but this is not essential - Solder wires to the pads for GND, CLK, DIO RST.
- Connect these wires to the Jlink.
On the Jlink it also has a VOUT and VIN. Connect the VOUT to VIN but I don't use this to power the radio.
Power the radio via the normal connectors to the battery, using a bench PSU - In the JLink software (JFLASH)
Create a new project.
Select the MCU, which I think is listed under Freescale
MK22FN512 (either of the 2 possible selections e.g. "allow security" - Select Connect in JFLash and check it can connect to the MCU
If it can't connect, check all your connections - When you have a connection.
Select Target -> Manual Programming ->Erase Chip - When the chip is erased it will now have copy protection removed.
- Download the patched bootloader
https://github.com/rogerclarkmelbourne/ ... loader.bin - Open this file with JFlash. Select address as 0 (zero)
- Then program with this file
Target -> Manual Programming -> Program and verify
The LED should be permanently on when the bootloader is running.
I hope this helps a little.