Also under Linux I could root my TabUltraC version 2023-11-22_07-29_3.5_9 46657f755 with the help of this guide.
The only difference is that I used
https://github.com/bkerler/edl. The difficulty is that I needed to install the modules mentioned in requirements.txt by hand adding python- for each of them (for example: pacman -S python-capstone or apt install python-capstone).
(
python3 setup.py build gave an error message, but that didn't matter.)
I could now read the boot_a image with:
./edl r boot_a boota.img
The rest is the same as in the above description.