Attempts to revert nRF52840 dongle to production bootloader fail

[Chris Pearson]

I'm attempting to revert an nRF52840 dongle to the production bootloader. This dongle has a SWD connector soldered on for use with J-Link, and I have no difficulties flashing my own software onto it.

The problem is when trying to revert it to the production bootloader using the documentation at this link. I've downloaded the hex file, extracted graviton_bootloader_mbr_v1.0.1-[nRF5_SDK_15.0.1-1.alpha_f76d012].hex, and flashed it to the dongle. Once reset, the red LED pulses as expected.

However, when I connect the nRF Connect Programmer to it, I see the following error:

2021-09-22T23:30:07.590Z INFO Using USB SDFU protocol to communicate with target
2021-09-22T23:30:07.608Z ERROR Error when calling version command: Error: Error message for known response code from DFU target: The data object didn't match firmware/hardware, or missing crypto signature, or malformed protocol buffer, or command parse failed.
2021-09-22T23:30:07.608Z ERROR Error when fetching device versions: TypeError: Cannot read property 'part' of undefined

Does anyone have a suggestion as to what might be the issue here? I'm suspecting I might have to repackage that hex file, or that I'm missing some other steps besides simply flashing it.

Thanks!

[Einar Thorsrud]

Hi,

This seems quite strange. I checked with the lead developer and he was not able to explain this, nor had he ever seen this behavior before. I will let you know if we come up with a workaround, but I suspect that will not happen until the next major release of nRF Connect for Desktop (that should happen in the not too distant future).

[Chris Pearson]

Okay, thanks for your help, Einar! I am impressed that the engineers at Nordic take the time to try to solve problems. That's not often seen, unfortunately.

One more thought about this problem: the only thing I can't delete and reinstall (easily, at least) are the drivers, so I'm left wondering about the DFU driver. Perhaps something has become corrupted there. Unfortunately the driver installer won't reinstall them, as it says "the best drivers for your device are already installed". 

I wouldn't mind beta-testing that upcoming major release of nRF Connect for Desktop. If you could pass that on to the lead developer, I'd appreciate it. I seem to be rather skilled at stumbling into strange, never before seen bugs... 

[Einar Thorsrud]

Hi,

I cannot say if the drivers are relevant or not at this point, but I will forward it. Regarding testing here are usually no public beta testing but I will mention that as well. It could be interesting in this case.