User defined fonts in VGA BIOS won't persist after performing shell command: CLS (Clear screen)
I've attached an example program with assembly code.
Run example program. Type CLS.
In original DOS the fonts persists.
It does not in DOSBOX (which is either a feature or a bug) :) Imho, a bug.
(It looks like you're doing a mode change or something - I dont think CLS in original DOS is doing a mode change - it probably only clears the screenbuffer and moves the cursor position, if i am not mistaken).