I also have the same issues and I run mad to find information online about it... Finally, I am not sure even how, I bumped into this, please help.
I was super happy with my device till when, after I while that I cold not use it (covid restrictions, RU955 was in another place) I turn it on and update the firmware... I was thinking it was the right thing to do but ... it is dead now! I tried everything I cold but even the serial console return a white screen. Can you help me to fix it please.
Let me know anytime.
All the best,