(I strongly suggest community members from US not respond for sanction concerns.)
I am not too deep into the coreboot build system either, but I can tell you that what you changed is part of SeaBIOS payload, which the coreboot build brings in fresh every time you compile. This is not part of coreboot per se, and because it is brought in fresh each time, no wonder your changes are getting lost.
You'll want to get the SeaBIOS sources yourself, make changes, build a binary, and insert it as a binary payload, instead of selecting SeaBIOS as your payload.
I am a student from tehran university in iran and I am interested to
booting system's and I research in this field I compiled compiled and build your project in the qemu and run successfully but i have problem if i want to changing message that show in the qemu.
for this I changing some printf() function in file /coreboot/payloads/external/Seabios/seabios/src/boot.c and then commit this changing and use make to recompiling project but nothing changing and then use "make clean " for deleting all the compiled file and recompile all of the project again by "make" and after this i see all of the my changing in the /coreboot/payloads/external/Seabios/seabios/src/boot.c is deleted and even my git commited is deleted .
how build system work this happens?
how to solve this problem and changing the massage in the qemu terminal?
and please explain to me source for this subject (i search in coreboot documentation but i can't find proper source)
With respect and apologies for any English grammatical errors in the text.
Regards Keith