Hello,
I recently dusted off an old FT-2800M that hadn't been used in years and ran into the same issue as reported in #3919. I believe I have a fix that I've attached to the #3919 page https://chirp.danplanet.com/issues/3919#change-28061. Getting Mercurial installed and set up to submit a patch seems a bit daunting to me. It was suggested that I post here in case someone else who's already set up for development would like to grab the code from the bug page, review it, and submit it. If not, I may take a stab at getting set up for the correct development process but it may be some time before I'm able to do so.
Summary of the change:
*It turns out that the radio uses a different IDBLOCK if it has been modified for extended transmit. The attached modified version of ft2800.py accepts both the standard and extended TX IDBLOCK values and uses the value that was read during a download for the upload process.*
Regards,
Andy