After updating my FreeBSD installation to 14.x on my old Raspberry Pi4 the system stopped booting. The problem is that the system cannot find the root filesystem anymore. It seem this a particular issue with some older revisions of Raspberry Pi 4 (especially those with 4GB+ RAM, like those ending in “B0T”) leading to MMC timeouts and failure to mount the root filesystem.

Fix

If you have For RPi 4 model with 4GB+ RAM, a common workaround is to edit the config.txt file in the EFI partition of your SD card. Add the following line under the [pi4] section: total_mem=4015.