@funkheld: Maybe instead of a "nrega" (or "nextregA" as used here by ChibiAkumas in "Z80 Assembly programming for the Spectrum Next": https://www.chibiakumas.com/z80/SpectrumNext.php ) you could use ; nextreg 45,a as listed on "https://wiki.specnext.dev/Extended_Z80_instruction_set".