Lenovo IdeaPad 3 17ADA05 BIOS Bricked

[SamyoFox]

Hi,

after doing a BIOS update my Lenovo IdeaPad 3 17ADA05 (Ryzen 3 3250U) doesn't boot anymore. The power LED turns on and the fans spin, but nothing else. I tried doing the Insyde BIOS Crisis Recovery (because the Phoenix/Insyde tool on the BIOS recovery page had identified it as an Insyde BIOS) but had no luck yet.
I found out that the correct file name for the BIOS file is E8Crisis.bin
I've tried a 128MB USB drive and a 4GB USB drive formatted as FAT. The 128MB drive has a activity LED, which turns on for a split second when turning on the laptop, but nothing else.

I did the following:
Turn off the laptop and disconnect AC power
Plug in the USB drive
Tried multiple key combos here (Fn+B, Fn+R, Win+B, Win+R)
Plug in the power cord and turn the laptop on without letting go of the keyboard buttons

But nothing happens. I've tried this both with and without the internal battery and CMOS battery connected.

Is there anything I missed or could try or do I have to use to a CH341A programmer?

Thanks!