2023-06-16 22:30:37 abandon mix board!
2023-06-16 22:30:37 abandon mix board!
2023-06-16 22:31:31 Chain[0]: find 126 asic, times 0
2023-06-16 22:31:33 Chain[1]: find 126 asic, times 0
2023-06-16 22:31:35 Chain[2]: find 0 asic, times 0
2023-06-16 22:31:37 Chain[2]: find 0 asic, times 1
2023-06-16 22:31:38 Chain[2]: find 0 asic, times 2
2023-06-16 22:31:38 Chain 2 only find 0 asic, will power off hash board 2
2023-06-16 22:31:38 ERROR_SOC_INIT: soc init failed!
The issue from logs still the same as from your previous logs removing the 3rd hashboard and keeping the two hashboards should run normally with decrease hashrate.
As suggested by mikeywith you can try Braiins OS to test if it is just an EEPROM issue but the problem is as you said before that it does not have the SD card slot have you checked the control board inside and maybe the SD card slot is hiding near Ethernet socket or beaglebone ?
Or if does not have an SD slot then your last hope is to use an OTG drive to micro USB to boot Braiins OS in your unit.