Blue flashing after bootloader installation

I think I have broken my Toniebox. When I connect it to the power supply, it lights up green for about 1 second and then flashes blue 5 times or more in quick sequence.
How can I restore the backup of my box or is it now completely broken?

I have followed the instructions and created a backup.pin. But I don’t know how to restore it.

Bootloader error codes:

In my attempt to solve the problem, I deleted the folder from the SD card (sd:/revvox/)
Can I just copy it back on?
And can I somehow read an error log from the box?

You can copy it to the SD card and it should work again.
In case you get blinking codes at startup see:

In my case, a faulty SD card extender was the cause.
Additionally, the SD card had some issues, which were solved by checking it with Windows. (check and repair).
After inserting the SD card directly into the slot, it worked again.