Sad that the new SPI-NAND driver prevents using the non-UBI variant at all.
The symptoms are discussed by @daniel and @981213 near this Belkin RT3200/Linksys E8450 WiFi AX discussion - #408 by daniel
If you want to revert the new NAND driver, you would need to revert the 10~ NAND commits near this in August:
https://git.openwrt.org/?p=openwrt/openwrt.git;a=history;f=target/linux/mediatek;hb=97e32e9702be7c7fab97d024ee336886e9faa0c7
|2021-08-27 |Chuanhong Guo|mediatek: mt7623: replace kconfig symbol for snand... |tree | commitdiff|
|2021-08-27 |Chuanhong Guo|mediatek: mt7629: manually add missing kconfig |tree | commitdiff|
|2021-08-27 |Chuanhong Guo|mediatek: mt7629: build with linux 5.10 |tree | commitdiff|
|2021-08-27 |Chuanhong Guo|mediatek: bmt: set default bmt oob offset to 0 |tree | commitdiff|
|2021-08-27 |Chuanhong Guo|mediatek: mtk-snand: check request size against chip... |tree | commitdiff|
|2021-08-27 |Chuanhong Guo|mediatek: attach bmt to the new snand driver |tree | commitdiff|
|2021-08-27 |Chuanhong Guo|mediatek: change dts to use the new snand driver |tree | commitdiff|
|2021-08-27 |Chuanhong Guo|mediatek: remove spi-nand hacks from 5.10 |tree | commitdiff|
|2021-08-27 |Weijie Gao|mediatek: enable new spi-nand driver for kernel 5.10 |tree | commitdiff|
|2021-08-27 |Weijie Gao|mediatek: add a new spi-nand driver for kernel 5.10 |tree | commitdiff|