1801 with OpenDM1801 running 12-22-2020 revision

Anything specifically related to the DM-1801 version of the firmware
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n0gik
Posts: 2
Joined: Mon Jul 19, 2021 3:07 am

1801 with OpenDM1801 running 12-22-2020 revision

Post by n0gik » Mon Jul 19, 2021 3:35 am

I have two 1801 running OpenDM1801. 12-22-2020 revision. I am able to read/write CP from/to both without issue.

The radios are working, but I went to update to latest Open revision on one of them and it won't go into firmware update mode (no green tx led).
The 2nd 1801 will go into the mode just fine - but haven't been brave enough to go further until I resolve or just learn what is going on with the first radio. They were bought at the same time and serial numbers are in-sequence.

I read that this may be a somewhat common problem and would like to know if there is an actual fix that doesn't require purchase of additional hardware to remedy. After all, the radios were ultra cheap for what they do and they are working good enough.

Any comments would be appreciated.

BTW, to the individuals doing the coding on this project, ya'll are spectacular AND your work is very much appreciated!

Thank you. 7-3 N0GIK - Matt

VK3KYY
Posts: 7481
Joined: Sat Nov 16, 2019 3:25 am
Location: Melbourne, Australia

Re: 1801 with OpenDM1801 running 12-22-2020 revision

Post by VK3KYY » Tue Jul 20, 2021 2:04 am

This is unfortunatly a known bug in the official firmware, which erases part of the CPU ROM memory used by the bootloader.

Its unclear under what conditions the official firmware does this, however once it happens, its not possible to update the fimware again, as the bootloader won't enter update mode.

The only solution to this is to connect a hardware programmer to the PCB and load a "modified" version of the bootloader which does not check the erased area of the CPU ROM

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