I have a raspi 3 with two attached external usb storages. A smaller ssd with the system (fat32/ext4) and a large hd (xfs) with data. My cmdline.txt tells the system from which UUID to boot from and it works flawlessly - until I plug in the data disk, which somehow always takes precedence over the ssd. There is no system on it, no boot directory or partiton, nor did I detect any boot flags in fdisk. Just a single partiton with some directories in it. Of course the system cannot boot from it, so I get a black screen and nothing happens.
What could be the cause of this?
Selected partition 1
Device: /dev/sdb1
Start: 2048
End: 11721043967
Sectors: 11721041920
Size: 5.5T
Type: Linux filesystem
Type-UUID: 0FC63DAF-8483-4772-8E79-3D69D8477DE4
UUID: F75C0B98-31E6-43C3-800B-235CD25AEAEF
Name: media
sudo cat /boot/cmdline.txt
dwc_otg.lpm_enable=0 console=serial0,115200 console=tty1 root=PARTUUID=2c192fba-02 rootfstype=ext4 elevator=deadline fsck.repair=yes rootwait
pi@raspberrypi
label: gpt
label-id: 4107ECD0-9D0D-4660-A66B-7B2138C2E0FF
device: /dev/sdb
unit: sectors
first-lba: 34
last-lba: 11721045133
/dev/sdb1 : start= 2048, size= 11721041920, type=0FC63DAF-8483-4772-8E79-3D69D8477DE4, uuid=F75C0B98-31E6-43C3-800B-235CD25AEAEF, name="media"
sudo blkid
/dev/sda1: LABEL_FATBOOT="boot" LABEL="boot" UUID="F661-303B" TYPE="vfat" PARTUUID="2c192fba-01"
/dev/sda2: LABEL="rootfs" UUID="8d008fde-f12a-47f7-8519-197ea707d3d4" TYPE="ext4" PARTUUID="2c192fba-02"
/dev/sdb1: LABEL="media" UUID="fa96f617-b3a4-46bc-ac52-029829f37616" TYPE="xfs" PARTLABEL="media" PARTUUID="f75c0b98-31e6-43c3-800b-235cd25aeaef"
bootcode.bin
, the Pi wouldn't magically boot from XFS.cmdline.txt
is a waste of time. Sorry I don't have any suggestions for you beyond that.