I agree, neither are U22. My point was that the U9H could see an 8TB HD, so I would expect no less from the U22 and that Android itself will support at least 512GB, so any less is not due to Android, but to a limitation in the minix hardware.
The microSD slot is not the same as connecting a (full sized) SD card through a USB adapter and the max capacity may also be different.
I am still waiting for my U22 to arrive.
Just FYI
!!
Until you've tested the compatability of
your specific external HDD's, or any other hardware or peripherals you personally plan on connecting, (or as the OP has prudently done by asking someone else to actually help test/check the facts for them beforehand).......
IMH(umble)O, I wouldn't make any hard assumptions that something will immediately work with the U22 (which you've yet to experience) just because it previously worked with your U9-H, a U1, or even your other various Android devices
!!
I can see why your thought process would immediately lead you to have such expectations based on the previous flagship MINIX products, & of course MINIX themselves actually labelling the U22 as the successor to the U9-H too, (as the U9-H was to the U1).
However, while they're still all intended to be "Android media hubs", the U22 is quite a different device to its predecessors really. (The significant differences between Android 9 when compared to 6 too notwithstanding.) Yes, the U22 still shares some common features with the previous MINIX Android media hubs & there are some obvious themes/similarities that MINIX have wanted to retain, but it really is quite a different device when you stand it up in direct comparison to the U9-H alone, or even the U1!!
Hopefully your device will arrive in the not too distant future. You can then directly experience everything for yourself, (& hopefully all of your existing hardware will also immediately function without any undue problems too
).