I have both Book8088 and Hand386.
Really wanted a working XT and bought Hand386 in addition just to look at it - i love pocket devices.
Book8088 wasn't normally working right from start - keyboard was unusable (Enter returns o, Backspace - 9, etc.). After and hour of testing other aspects (with autoexec.bat 😀) bad pixels appeared on top on screen. Guy selling the device wasn't helpful, he just passed the problem to dev and he's answer back, and i did mention that Fn+F7 returns mode 80o, not mode 80<cr> as it should. I've cleaned the kbd chip as he suggested, nope. Okey, opened dispute, left the device to some rest.
Hand386 - i actually liked it. It reminds me of some old handheld devices. Rubber keyboard is ok, you can plug external PS/2 kbd and mouse, and a monitor. Would love having a COM port there - it would be a good network setup device. Problems - quick discharge with external devices connected and external power is not enough for it. After working for some time on external display, i notices that internal display become very bright, in sense like it's contrast/brightness controls went to max. Seller wasn't helpful in this case either. But - Ian Scott on Youtube suggested setting unknown to display controller mode and it worked for me - i've set an extended VESA mode, display said "Auto" and colors were fixed. At that time sticker on the front started to fall off. Removed. Would love to have an advice how to program RTD2660 controller, it has some kind of flashing interface (4 very small pads).
Overall - nice device to run an old game for 5 mins and have that nostalgia satiated. Kind of SoundBlaster would make it a hit, imagine having Second Reality in your pocket 😀
Meanwhile, dispute for Book8088 was resolved, i've disassembled it. 3.5 connector fallen off together with some traces. No probs, that's fixable. Removed and cleaned all socketed chips. After cleaning chip labelled XT IO, keyboard started to work. Good. Soldered connector, put together, time to use. Still have bad pixels, but well.
Next, flashed Sergey Kiselev BIOS - https://github.com/skiselev/micro_8088 and made a CGA firmware with CP866 (that "CGA" eprom chip contains only character tables).
All good.
Unsoldered soviet-era 8088 clone chip from my old broken board - it worked in Book8088 😀 Made my day, really.
Found incompatibilities: 3-Demon draws garbled sprites, fixed after some reversing research (BIOS was not saving DX register in int 08 handler). Turbo Basic hangs on file load - found the answer here on Vogons 😀
I would love to have ability to connect at least external keyboard to Book8088. Having ISA8 connector is not practical for me, it's a laptop by design. VGA/Mouse/Joystick/Keyboard would be much more useful.
So i wouldn't recommend Book8088 - but if you have no XT and want one - that might be your choice.
P.S. Placed all stuff i made so far here https://github.com/jinshin/Book8088