MOX (A+C) - USB3 still NOT working.
Rolled back to 5.4.4 where the USB3 HDD works just fine.
On 5.4.4:
# cat /sys/kernel/debug/usb/devices
T: Bus=03 Lev=01 Prnt=01 Port=00 Cnt=01 Dev#= 2 Spd=5000 MxCh= 0
D: Ver= 3.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 9 #Cfgs= 1
P: Vendor=0bc2 ProdID=3322 Rev= 1.00
S: Manufacturer=Seagate
S: Product=Expansion Desk
S: SerialNumber=NAAAF32S
C:* #Ifs= 1 Cfg#= 1 Atr=c0 MxPwr= 0mA
I:* If#= 0 Alt= 0 #EPs= 2 Cls=08(stor.) Sub=06 Prot=50 Driver=usb-storage
E: Ad=81(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=02(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
I: If#= 0 Alt= 1 #EPs= 4 Cls=08(stor.) Sub=06 Prot=62 Driver=usb-storage
E: Ad=81(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=02(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=83(I) Atr=02(Bulk) MxPS=1024 Ivl=0ms
E: Ad=04(O) Atr=02(Bulk) MxPS=1024 Ivl=0ms
# lsusb -vt
/: Bus 03.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 5000M
|__ Port 1: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 5000M
/: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=xhci-hcd/1p, 480M
/: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=orion-ehci/1p, 480M