Since there are now good alternatives to my firmware version, I will save myself the effort in the future.
My web flasher can still be used to free LV07 and LV06 miners. See my wiki for more information: https://github.com/un-painted-org/ESP-Miner/wiki
Directions for LV07
For LV07 firmware, I now refer to @r3mko: https://github.com/r3mko/ESP-Miner-LV07/releases
His firmware is compatible with mine and can be installed without any problems via AxeOS.
Directions for LV06
After installing my firmware, the official firmware can be installed without any problems.
Official firmware: https://github.com/bitaxeorg/ESP-Miner/releases