Thank you very much for the guide! My android installation bootlooped, so I had to follow it one more time.
Windows was very slow, so I wiped Windows and kept only Android partition and extended it to 53 GB using gpt.bin mod – it was compatible with Chuwi hi12.
I need root to limit CPU to 1600 MHz (kernel adiutor app), else it would freeze on high load. Also I had to use app to keep wakelock (for this root is not needed), because my unit would freeze if it enters deep sleep too.
Links to downloads are sadly dead, but thanksfully I still found them archived on my drive. I decided to make a mirror:
https://drive.google.com/drive/folders/1q3mOwy–XFtJQUgfMChWT4m4IGUB-iJN?usp=share_link
It includes moded gpt.bin, chuwi-android-fs-1.0.4-install.zip and hibook-Toolbox with new ADB binaries (old ones were not working for me)
