Thanks ever so much for answering! As requested …
$ sudo lsblk -o name,fstype,label,size,ro,type,mountpoint,partuuid,uuid
NAME FSTYPE LABEL SIZE RO TYPE MOUNTPOINT PARTUUID UUID
mtdblock0 16M 0 disk
mmcblk0 28.9G 0 disk
└─mmcblk0p1 ext4 28.9G 0 part / f7138353-01 19e46d43-2ef4-45d3-be06-ceee5e2cb50f
In case it’s relevant, here’s some more copy-paste of what happens when I unplug and then replug the flash drive. I unplugged after the first line of output and before the second. When this operation is completed, the lsusb command returns exactly the same info as above.
$ dmesg | tail -n 20
[253214.565145] usb 4-1: USB disconnect, device number 2
[253266.684547] usb 4-1: new high-speed USB device number 3 using xhci-hcd
[253266.833556] usb 4-1: New USB device found, idVendor=13fe, idProduct=1d00, bcdDevice= 1.10
[253266.833582] usb 4-1: New USB device strings: Mfr=1, Product=2, SerialNumber=0
[253266.833600] usb 4-1: Product: 2301 Boot Rom
[253266.833617] usb 4-1: Manufacturer:
[253266.835830] usb-storage 4-1:1.0: USB Mass Storage device detected
[253266.837272] scsi host0: usb-storage 4-1:1.0
[253267.841016] scsi 0:0:0:0: Direct-Access 2301 Boot Rom 1.00 PQ: 0 ANSI: 0 CCS
[253267.841544] sd 0:0:0:0: Attached scsi generic sg0 type 0
[253267.889588] sd 0:0:0:0: [sda] Attached SCSI removable disk
I do understand that the kernels here come from Armbian. Indeed that was a good reason to raise my question here instead: I was hoping to hear from somebody who has managed to get the rock64 working without too much heroic low-level intervention!
Thanks again for taking an interest.