L5 Modem BM818 - Open Firmware


Biktorgj has made a lot of progress on freeing the firmware on the Quectel EG25-G modem used by the PinePhone. He hasn’t touched the proprietary radio firmware, but has managed to replace a lot of the other stuff which is frankly incredible. I didn’t think that it would be possible–I guess that it is one of those issues where nobody has really tried before, so everyone assumed that it would be impossible.

I look forward to seeing what he can do with the BM818 firmware. I wish that I could assist in some way to help him, but this looks like black magic to me.


Reverse engineering is a tedious art. I’ve dabbled in it, but saying I’m an “artist” would be like me bragging to Van Gogh that I know what the difference between red and blue is.

Very cool that he’s giving that modem a shot, I hope progress comes easy.


If Bigtorgj is ever in need of more stuff to do there is also the Simcom SIM7600 to work on…

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Honestly I would like to see some Thales modem for L5. As Thales could manufacture some of their products in Germany or France and give as another choice for a product not made in PRC.
There are Thales modems in the appropriate size for Librem 5.
But anyways. Let us first have BM818 right and then we could think about options.


L5: Broadmobi BM818 Booting…

I couldn't leave all the @Puri_sm #Librem 5 users missing all the fun!
Just getting started, Broadmobi BM818 Booting our custom bootloader and starting (and crashing mid boot) the Linux kernel from the modem distro! pic.twitter.com/wV5rHNgVl9

— Biktor (@biktorgj) July 17, 2022

L5: Modem: Debug UART and EDL access…


Have you bought one and confirmed that it does indeed physically fit inside the Librem 5??

No, but the confidence that it will fit is pretty high, as it is on paper exactly the same as the original L5 Modem (30mm x 42mm x 2.3 mm) and as JR-Fi already successfully fitted a significantly larger modem ( 31.4 x 42 x 3.8) which is proof that there is some tolerance if one is ready to adjust the case.


The Open Modem Firmware for L5 it’s getting closer to it working stage.
Benefits for L5:

  • Power save
  • Temperature save
  • Free as Freedom
  • Security
  • Privacy
  • Hackable
  • Stability