Many issues can be solved by flashing a custom firmware, updating to the last stock version should be your LAST resort, I believe the "2019-08-08" version can still be unlocked, so do check Asic.to and AwsomeMiner for that.
The kernel log suggests that all 3 hash boards are dead
1st hashboard
driver-btm-c5.c:13449:bitmain_c5_init: retry Chain[J6] has 0 asic
2nd hashboard
driver-btm-c5.c:13449:bitmain_c5_init: retry Chain[J7] has 0 asic
3rd hashboard
driver-btm-c5.c:13449:bitmain_c5_init: retry Chain[J8] has 0 asic
This, in a nutshell, suggests that your miner is completely DEAD, however, the kernel log can only tell you so much, other reasons such as a bad PSU or/and bad control board can cause the same issue.
There is a ton of troubleshooting that you have to do, start with the following:
1- Replace the PSU.
2- Flash a different firmware.