External USB blocks ssh access

Hi folks

I experiment a strange issue when I connect an external USB HD to a RockPro64 running DietPi: v10.4.2.
The linux version is : Linux DietPi 6.18.29-current-rockchip64 #1 SMP PREEMPT Mon May 11 06:20:52 UTC 2026 aarch64

When I ssh and plug the HD, everything is working fine

Before

NAME FSTYPE LABEL SIZE RO TYPE MOUNTPOINT PARTUUID UUID
mtdblock0 16M 0 disk
mmcblk2 29.1G 0 disk
└─mmcblk2p1 ext4 29.1G 0 part / 0db3c612-01 16fd56b1-1af3-4832-b584-e15c71d16b10
mmcblk2boot0 4M 1 disk
mmcblk2boot1 4M 1 disk
zram0 swap 1.9G 0 disk [SWAP] 071aa062-818d-4e6f-905d-a2678b4a4ea7
nvme0n1 ext4 931.5G 0 disk /mnt/dabou 2e0b34b5-bdd1-4f5d-bc7c-8af0fb1879c0

/dev/nvme0n1: UUID=“2e0b34b5-bdd1-4f5d-bc7c-8af0fb1879c0” BLOCK_SIZE=“4096” TYPE=“ext4”
/dev/mmcblk2p1: UUID=“16fd56b1-1af3-4832-b584-e15c71d16b10” BLOCK_SIZE=“4096” TYPE=“ext4” PARTUUID=“0db3c612-01”
/dev/zram0: UUID=“071aa062-818d-4e6f-905d-a2678b4a4ea7” TYPE=“swap”

When plugged

NAME FSTYPE LABEL SIZE RO TYPE MOUNTPOINT PARTUUID UUID
sda 1.8T 0 disk
└─sda1 ext4 1.8T 0 part 2ce7a6c3-e2d4-41cd-a44b-8fdb73007400
mtdblock0 16M 0 disk
mmcblk2 29.1G 0 disk
└─mmcblk2p1 ext4 29.1G 0 part / 0db3c612-01 16fd56b1-1af3-4832-b584-e15c71d16b10
mmcblk2boot0 4M 1 disk
mmcblk2boot1 4M 1 disk
zram0 swap 1.9G 0 disk [SWAP] 071aa062-818d-4e6f-905d-a2678b4a4ea7
nvme0n1 ext4 931.5G 0 disk /mnt/dabou 2e0b34b5-bdd1-4f5d-bc7c-8af0fb1879c0

/dev/nvme0n1: UUID=“2e0b34b5-bdd1-4f5d-bc7c-8af0fb1879c0” BLOCK_SIZE=“4096” TYPE=“ext4”
/dev/mmcblk2p1: UUID=“16fd56b1-1af3-4832-b584-e15c71d16b10” BLOCK_SIZE=“4096” TYPE=“ext4” PARTUUID=“0db3c612-01”
/dev/zram0: UUID=“071aa062-818d-4e6f-905d-a2678b4a4ea7” TYPE=“swap”
/dev/sda1: UUID=“2ce7a6c3-e2d4-41cd-a44b-8fdb73007400” BLOCK_SIZE=“4096” TYPE=“ext4”

I can mount it

root@DietPi:~# mount -a
root@DietPi:~# ls -la /mnt/dabou-ext
total 36
drwxr-xr-x 6 dietpi dietpi 4096 Dec 9 2021 .
drwxr-xr-x 8 root root 4096 May 19 18:32 ..
drwxr-xr-x 3 root root 4096 Dec 9 2021 dietpi-backup
drwxr-xr-x 6 dietpi dietpi 4096 May 5 09:11 dietpi-sync
drwx------ 2 dietpi dietpi 16384 Dec 9 2021 lost+found
drwxrwxrwx 2 dietpi dietpi 4096 Dec 10 2021 nfs

Here is the content /etc/fstab

#----------------------------------------------------------------

PHYSICAL DRIVES

#----------------------------------------------------------------
UUID=16fd56b1-1af3-4832-b584-e15c71d16b10 / ext4 noatime,lazytime,rw 0 1
UUID=2e0b34b5-bdd1-4f5d-bc7c-8af0fb1879c0 /mnt/dabou ext4 noatime,lazytime,rw,noauto,x-systemd.automount
#UUID=7FFE-6C17 /mnt/dabou-usb exfat defaults,nofail,flush,uid=1000,gid=1000 0 0
UUID=2ce7a6c3-e2d4-41cd-a44b-8fdb73007400 /mnt/dabou-ext ext4 noatime,lazytime,rw,noauto,x-systemd.automount=5s 0 2

Unfortunately, If I reboot the RockPro64 and tries to ssh, than I cannot and it is needed that I unplug the HDD and that I remove the power cable, etc

What is then the issue and how to fix it ?

Cheers

Charles M.

Can you verify that the system is booting when the HDD is connected, via UART or a connected monitor?

Is the USB HDD only powered via USB? If this is the case it is probably a power issue.

It’s also possible that it’s trying to boot via USB when the HDD is connected.