Hi!
Just so we’re all on the same page, what versions of fastboot are you using and did you have success with it?
fastboot --version
I tried on different Linux boxes:
fastboot version 33.0.3-debian
Board does not react afterfastboot reboot
and the board only shows
brom_ver 8
[APP][E] protocol_connect failed, exit.
fastboot version 34.0.4-android-tools
exactly the same