If I understand correctly now, the Rider v2 has stopped working?

Bootloader update is a fairly dangerous operation and should be done with the necessary precautions.
For example, the battery must first be fully charged.
It is even better to have the power supply added during that update.
If the voltage is lost, you run a great risk that the flash will not be terminated completely, as a result of which the boot loader is incomplete.
The boot loader can be compared to the BIOS of a PC, all hardware is booted from that fixed program in the BIOS and in the case of the Rider v2 the boot loader.

The update can be done from any SD card below or equal to 2GB, basically only the "system" file is needed to start the process which takes only seconds but takes as many seconds to destroy your device when the voltage drops.

I have a Rider v2 myself and use as a bootloader 5.5128 with satisfaction, the navcore is the latest available 9.501 and I also flashed the GPS chip in connection with the WNRO problem, so the problem with weekly reset and a quickgpsfix update is a thing of the past for me.

Now that the problem of your Rider v2 may become unresponsive, I have a special navcore here that has been successfully used by a few other users of another forum to make the device usable again after a wrong boot loader update.
I have never tested it myself and I am happy with that if you know what I mean.

Some knowledge of the use of software is necessary, if you do not know exactly what you are doing, the problem may only increase. I can offer you that when the Rider v2 starts normally again I can compile a working SDHC card for you with every map you want on it, it will be available via my own server via a private link, but then I need your ttgo.bif file first to patch it all.

I'll see if I can make this navcore available here for general use via the Megasync servers, including the various bootloaders, in a subsequent post.