I boot the latest FP64 and bionicpup64 from a usb stick (sdc) but have the save files on the sda (SSD, frugal install) on a UEFI PC. I boot from usb since I occasionally boot ubuntu on sda (I tried to multiboot from SSD but was complicated due to ubuntu) usb. I use an external HD attached to usb 3.0 (usually mapped as sdb) for large file storage.
sdb is auto-mounted using pmount option on boot. I noticed this sdb is occasionally remapped to sda and causes problems with my scripts that access external HD.
There is no fstab on my PC. Is there a reliable way of always having the external HD mounted as sdb? Attached is from command of lsblk.