the Channel's DMR id is designed to override the global ID for that given channel.
Of course, if you don't save the channels settings permanently, it will be temporary, but there is another temporary ID override:
#, #, #, SK2 + #
Now you permanently change the radio ID, by validating the new ID with SK2 + GREEN, or temporary (until power cycling, or entering empty or 0 ID) if you press GREEN only.
Of course, it's documented. It's always good to spend some time reading the manuals
https://github.com/LibreDMR/OpenGD77_Us ... mber-entry
BTW, I just tried both methods to set a 12345678 ID, and it works.
No need to remind us the max ID number, it's a well known value
Cheers.
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Daniel