This target is new to me, maybe I don't understand something.
I installed a master build, it seems to work OK, I didn't test it thoroughly yet. But sysupgrade doesn't work at all.
Today I made another build and tried to sysupgrade. The device seem to flash, but it's unreachable after a reboot. I could reach the device only in failsafe mode. And it appeared that the Openwrt version was still old. So it didn't flash to a new one.
Writing to firmware partition using mtd command works OK. So I flashed a new one.
So the question is it a bug, or sysupgrade is not supposed to work properly on this device?
But both devices share the same SoC, MT7620A. Good indication for same bug.
Filing two different bugs (for similar/same symptoms) inflates the list, but lowers probabily that somebody cares.
I have the same hardware and don't have any problem. But remember, you have to very patient. The upgrade and first init after that sometimes takes about 15 minutes.
Yes, it is strange. But probably I will have to conect to serial port do debug it.? Probably something needs to timeout and than go further ? I just guessing