Bricked device

[Fiannax]

Hello,

after an attemp to switch to UF2 Bootloader from Open Bootloader my Makedriary nRF52840 MDK USB Dongle stopped working (now shows only the green led always on) and it doesn't get recognized by my pc. I noticed this guide (wiki.makerdiary.com/.../) to unbrick it but it requires a second makerdiary dongle. My question is: is it possible to use the original Nordic nrf52840 dongle that I already own to do the same?

Thanks

[polob12]

Hi, did you manage to flash the nRF52840 MDK with a Nordic nRF52840 Dongle ? I also have the green led permanently on. I can access the chip with openocd via a raspberry pi. I can also erase it and flash another hex/bin and verify the flashed image, but it just stays the same. The green light won't go out, is always on and device is not even recognised in windows or debian.

Open On-Chip Debugger 0.12.0+dev-00699-ge09bb72da (2024-08-27-18:42)
Licensed under GNU GPL v2
For bug reports, read
	http://openocd.org/doc/doxygen/bugs.html
Info : BCM2835 GPIO JTAG/SWD bitbang driver
Info : clock speed 999 kHz
Info : SWD DPIDR 0x2ba01477
Info : [nrf52840.cpu] Cortex-M4 r0p1 processor detected
Info : [nrf52840.cpu] target has 6 breakpoints, 4 watchpoints
Info : [nrf52840.cpu] Examination succeed
Info : [nrf52840.cpu] starting gdb server on 3333
Info : Listening on port 3333 for gdb connections
[nrf52840.cpu] halted due to breakpoint, current mode: Thread 
xPSR: 00000000 pc: 0x213c0a0a msp: 0x0a0a0a08
Info : Listening on port 6666 for tcl connections
Info : Listening on port 4444 for telnet connections
Info : accepting 'telnet' connection on tcp/4444
Info : nRF52840-QI/CAAA(build code: D0) 1024kB Flash, 256kB RAM
Info : Mass erase completed.
[nrf52840.cpu] halted due to breakpoint, current mode: Thread 
xPSR: 0x01000000 pc: 0xfffffffe msp: 0xfffffffc
** Programming Started **
Info : Padding image section 0 at 0x0004aaa1 with 3 bytes (bank write end alignment)
Warn : Adding extra erase range, 0x0004aaa4 .. 0x0004afff
** Programming Finished **
** Verify Started **
** Verified OK **
[nrf52840.cpu] halted due to breakpoint, current mode: Thread 
xPSR: 00000000 pc: 0x213c0a0a msp: 0x0a0a0a08
** Programming Started **
Info : Padding image section 0 at 0x0004aaa1 with 3 bytes (bank write end alignment)
Warn : Adding extra erase range, 0x0004aaa4 .. 0x0004afff
** Programming Finished **

I would like to try the DAP method you linked to but am struggling to connect the right pins on the Nordic nRF52840 Dongle which is the DAPLINK

Any guidance would be appreciated, seems to me the Nordic nRF52840 Dongle does not have a RESET pin to connect ?

[Fiannax]

In the end I solved using a chep debug interface (https://it.aliexpress.com/item/1005003587741362.html?spm=a2g0o.order_list.order_list_main.72.41923696u5LcUo&gatewayAdapt=glo2ita) and following this guide (wiki.makerdiary.com/.../)