https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87374
--- Comment #4 from Thomas Preud'homme <thopre01 at gcc dot gnu.org> --- My approach was wrong, fundamentally -mslow-flash-data and -mword-relocations cannot both be in effect since there is then no way to load an address: - -mslow-flash-data forbids literal pools - -mword-relocations forbids MOVW/MOVT I've written a patch to make the two options conflicts. Testing it now.