/dev/mmcblk0 is now suddenly /dev/mmcblk1

[ungeskriptet]

I did a fresh install on a 64GB SD Card for my Raspberry Pi 4B only to notice that /dev/mmcblk0 is now /dev/mmcblk1. I also saw systemd say "A start job is running for /dev/mmcblk0". Is there a way to change it back?

[ewtoombs]

I saw the same thing. I have a Raspberry Pi 4 Model B. Changing mmcblk1 back to mmcblk0 isn't a real solution. The correct thing to do is give the boot filesystem a label and mount by label instead. That's what I did. Device node names are subject to race conditions and should never be relied upon. For instance, if somebody attaches a USB sdcard reader to the raspi's USB port, what happens on boot? Exactly. You don't know.

This is a very serious bug. The default raspberry pi 4 64-bit image will not work out of the box until it is fixed.