I saw, few weeks ago, a post which talked (very quickly) about this problem, but without a reliable solution.
I tried to root my Kospet Prime. For this, I installed Magisk Manager, and go to “Install” to patch the boot.img, as the classic process want.
BUT: Magisk don’t browse normally for searching boot.img. It just open a sort of folder, called “Docs” which only list the .jpg and .png files. Impossible to browse more than that.
So impossible to reach my boot.img file.
However, the method by patching boot.img on another device with Magisk don’t works.
So, on the watch, I renamed “boot.img” by “boot.jpg” . Magisk Manager, as said before, saw it , and flashed it ! Astonishing, but true. Yes, the main is the content, not the name, but stuning…
The rest is quiet classic, magisk-patched.img on the PC. Renamed on “boot.img” in the Firmware folder, and flashed with Flash tool. I only selected the boot line.