I updated the bootloader firmware of my Pi 4b according to this tutorial. It was still on 13701 (May 10, 2019) and the update showed version 137ab (Sep 10, 2019).
After „sudo reboot“ the Pi didn‘t boot anymore.
The bootloader seems fine, I even did the recovery method and the green LEDs blink four times when I start the Pi without sd card. But unfortunately my former SD card with my whole system won‘t boot anymore. Is there any chance I can rescue it? This would save me lots of hours of work (and some files I didn‘t backup before).
I don‘t even have a micro-HDMI adapter since I forgot to order it on day 1 and never needed it until today. The Pi 4 is/was running headless (Buster lite) for months without a problem. It’s a 128 GB Sandisk sd card with FAT32/ext4 and I‘m using the original Raspberry power adapter. There‘s nothing connected to the Pi except a network cable (LAN). At the beginning it seems to start up fine and both the LEDs blink without a special pattern. But after some seconds it just stops.
Maybe the problem was that my buster wasn‘t on the most recent version and I haven‘t run a dist-upgrade or full-upgrade before (which wasn‘t mentioned in the guide)?
Thanks for your help!