Hey, cool -- I'm doing sth similar for Arduino on ESP:
https://github.com/spapadim/ucglib (warning: stuff committed is untested, just compiles)
Was wondering if you also had any issues with reading font data. My ILI9341 arrived yesterday from China, got most stuff to run easily (just a couple of yield()s to avoid WDT resets on long-running draw commands), except fonts. objdump shows correct data, but when the program runs, it reads seemingly random bytes out of those arrays. I noticed that you stripped out the linker subsection stuff, so I also temporarily tried using just "plain" uint8_t* for font data, but that did nothing either.
Any experience you can share would be appreciated -- thanks!
EDIT: Actually, nevermind, my bad -- it was the linker subsection stuff, my bad (talk about missing what's staring right at you, in objdump output the section name was right there -- I had forgotten to strip it from ucg.h as well). Still haven't solved it, but at least I know what I'm trying to fix.