Which mtd changes are you talking about?
BTW, I patched u-boot, so that the strange in-between step with Mafketels sysupgrade can be skipped, and installing 21.02 can be done the 'normal' way, using an initramfs image. This doesn't add much when you are upgrading from an older version. But 21.02 is maybe the last version which can be installed with the unpatched u-boot. Master doesn't load. It's kernel is decompressed >8MiB.