I performed sysupgrade from 19.07.7 to 21.02.1 and encountered this warning . I regret for ignoring such warning - the device then bricked because of exactly the reason discussed there: kernel partition size mismatch. I then managed to build OpenWrt 21.02.1 in order to do a ramdisk-boot. However it …

Using 80800000 as the load address will crash because this is the same area of RAM that the uncompressed kernel will occupy. As decompression proceeds, the compressed image gets overwritten before it is finished. Use an address of 82000000 instead. This is 32 MB past the start of the physical RAM…

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Failed to ramdisk-boot OpenWrt 21.02.1 on WNDR4300v1

Installing and Using OpenWrt

badulesia November 18, 2021, 8:45am 3

You have the answer in this thread ... from yesterday