spi nor flash (/dev/mtd0) not acessible
this happens during boot on birch:
[ 14.792318] m25p80 spi0.0: no pinctrl handle
[ 14.795613] m25p80 spi0.0: unrecognized JEDEC id bytes: ff ff ff ff ff ff
[ 14.802913] m25p80: probe of spi0.0 failed with error -2
so there driver does not probe correctly and there's no /dev/mtd0
at all.