I recently plugged in a 4TB Seagate Expansion hard drive and it worked fine.

 

After rebooting the Rockpi4B via 'sudo reboot'  the drive  is not recognised -  dmesg shows:

[    3.877060] sd 1:0:0:0: [sdb] Unit Not Ready
[    3.877082] sd 1:0:0:0: [sdb] Sense Key : 0x4 [current] 
[    3.877094] sd 1:0:0:0: [sdb] ASC=0x44 <<vendor>>ASCQ=0x81 
 

Any ideas?

What happens if you disconnect and reconnect the hard drive?

I'll confirm tomorrow (the drive and system are installed at our holiday house, 50km from me) - I'm 99% confident it will work.

Sure enough,  unplug/replug works...

[75734.552263] usb 6-1: USB disconnect, device number 2
[75737.559808] usb 6-1: new SuperSpeed USB device number 3 using xhci-hcd
[75737.581298] usb 6-1: New USB device found, idVendor=0bc2, idProduct=2037, bcdDevice=19.01
[75737.581339] usb 6-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[75737.581362] usb 6-1: Product: Expansion HDD
[75737.581381] usb 6-1: Manufacturer: Seagate
[75737.581400] usb 6-1: SerialNumber: 00000000NAC5MKA3
[75737.583286] usb 6-1: UAS is ignored for this device, using usb-storage instead
[75737.583317] usb-storage 6-1:1.0: USB Mass Storage device detected
[75737.584389] usb-storage 6-1:1.0: Quirks match for vid 0bc2 pid 2037: 800000
[75737.584713] scsi host1: usb-storage 6-1:1.0
[75738.600671] scsi 1:0:0:0: Direct-Access     Seagate  Expansion HDD    1901 PQ: 0 ANSI: 6
[75738.601867] sd 1:0:0:0: Attached scsi generic sg0 type 0
[75743.224634] sd 1:0:0:0: [sda] Very big device. Trying to use READ CAPACITY(16).
[75743.224837] sd 1:0:0:0: [sda] 7814037167 512-byte logical blocks: (4.00 TB/3.64 TiB)
[75743.224845] sd 1:0:0:0: [sda] 4096-byte physical blocks
[75743.225155] sd 1:0:0:0: [sda] Write Protect is off
[75743.225164] sd 1:0:0:0: [sda] Mode Sense: 47 00 00 08
[75743.225490] sd 1:0:0:0: [sda] Write cache: enabled, read cache: enabled, doesn't support DPO or FUA
[75743.909269]  sda: sda1
[75743.910741] sd 1:0:0:0: [sda] Attached SCSI disk

 

Not sure but I might have had similar issues on restart but do not know anymore with which board. Anyway hard to tell what's the cause for this...

Interestingly,  there are two hard drives connected - a WD 2TB drive and the new Seagate 4TB.  The WD 2TB survives  the reboot no  problems.

power 2 spinning drives drawing to much power starting at sane time...

16 hours ago, tellytinker said:

power 2 spinning drives drawing to much power starting at sane time...

I considered that -  however  the RockPi  page states:

How much mA can i get from the USB 3 and 2 ports for charging or use a 2.5" disk?

The upper USB3.0 OTG has one dedicated current limit control which is 1.45A. The rest USB 3.0 HOST and the two USB 2.0 HOST share a current limit control of 3A together

 

I asked Radxa  - they advice a 30W USB PD power supply is needed to power two hard drives - I currently only have an 18W one. I've ordered a 30W power  supply and will replace it ASAP and report the results.

OK so I changed over to a 30W USB PD power  supply today, and still  had no 4TB drive  after a reboot.

Originally,  I had both hard drives connected to the USB 3 ports.  I moved one of them to a USB 2 port and now both drives seem to survive the reboot. The 'working' configuration is as per https://photos.app.goo.gl/frowcFeJCpDCjkGZ7