Options for flashing nrf9151 with production firmware without J-link.

[Joe01]

Hi all,

I've built a custom nRF9151 board, which is successfully responding to the basic factory AT commands. It won't accept a CFUN=1 command though, presumably because it's still loaded with the factory firmware. 

I've only got access to a PicoProbe at the moment, which has worked great for flashing application programs over SWD, but I'm now trying to change the modem firmware to the production version and I can't find any way to do this without MCUBoot or a J-Link adapter. 

Do I have any options other than buying a J-Link Edu Mini? 

Thanks!

[Achim Kraus]

There are some boards using a onboard-RP2040 probe and https://probe.rs/ with github.com/.../modem_updater, e.g. nrf9151-feather . For the feather it works well, I don't know, if it works for a RP2040 stand alone probe. 

[Simon D-M]

Hi,

I've only got access to a PicoProbe at the moment, which has worked great for flashing application programs over SWD, but I'm now trying to change the modem firmware to the production version and I can't find any way to do this without MCUBoot or a J-Link adapter. 

Do I have any options other than buying a J-Link Edu Mini? 

Theoretically, the nRF9151 modem firmware only needs a SWD connection to be updated. I'm not sure how much our tools support non-jlink debugger though. I'll ask internally and get you back on that.

Also, If you already have one of our Dev Kit, you can use its on-board debugger to connect to other boards. You can use the "DEBUG OUT" port with a JTAG 10 pins cable (or on some of them you also have a normal 2.54mm pin header that has the pin exposed).

I've built a custom nRF9151 board, which is successfully responding to the basic factory AT commands. It won't accept a CFUN=1 command though, presumably because it's still loaded with the factory firmware. 

Out of curiosity, what modem firmware do you have on your chip? You can check using the AT+CGMR command.

Best regards,

Simon D-M

[ethancole53]

I was wondering about this as well. If the modem firmware update only requires SWD access, it would be great if tools like probe-rs or OpenOCD eventually offered better support for this workflow. Requiring a J-Link for a one-time production firmware update can be a bit inconvenient, especially for hobbyists or small prototype runs. Looking forward to hearing if there's an officially supported alternative. basketball stars

[Simon D-M]

Hi,

Currently, I believe the only official tool to update the modem firmware is JLink. But theoretically everyone can do it as long as they have access to SWD. It is just a matter of which other tool has implemented it. The whole documentation on how to update the modem is available here.

It is also possible to update the modem firmware through DFU or FOTA if your application supports it. This is, for example, the intended method on the Thingy:91 (link).

For hobbyists, maybe the best "fully official" way of doing it is to use another Nordic DK (that has the "new" nRF5340 debugger) and connect its "DEBUG OUT" port to your custom board (link).

Best regards,

Simon