FS#3890 - Kernel is wrongly encapsulated

[openwrt-bot]

Mijzelf:

Device ZyXEL P2812HNU-F1

Flashing the sysupgrade of 21.02rc3 bricks the router. Apparently there is a checksum error in the flashed kernel:

NAND read: device 0 offset 0x60000, size 0x200000
2097152 bytes read: OK

Booting kernel from Legacy Image at 80800000 ...

Image Name: MIPS OpenWrt Linux-5.4.124
Created: 2021-06-13 22:02:19 UTC
Image Type: MIPS Linux Kernel Image (lzma compressed)
Data Size: 2465658 Bytes = 2.4 MiB
Load Address: 80002000
Entry Point: 80002000
Verifying Checksum ... Bad Data CRC
ERROR: can't get kernel image!

Further, don't know if it is related, booting the initramfs-kernel.bin doesn't work either:

P-2812HNU-F1 # bootm $fileaddr

Booting kernel from Legacy Image at 81000000 ...

Image Name: MIPS OpenWrt Linux-5.4.124
Created: 2021-06-13 22:02:19 UTC
Image Type: MIPS Linux Kernel Image (lzma compressed)
Data Size: 5608365 Bytes = 5.3 MiB
Load Address: 80002000
Entry Point: 80002000
Verifying Checksum ... OK
Uncompressing Kernel Image ... LZMA: uncompress or overwrite error 7 - must RESET b


When tftpbooting the kernel found in the imagebuilder,
openwrt-imagebuilder-21.02.0-rc3-lantiq-xrx200.Linux-x86_64/build_dir/target-mips_24kc_musl/linux-lantiq_xrx200/zyxel_p-2812hnu-f1-kernel.bin
the kernel boots fine (and uses the rootfs which is currently flashed in ubi), and has the same size and timestamp as the one from sysupgrade:

bootm $fileaddr

Booting kernel from Legacy Image at 81000000 ...

Image Name: MIPS OpenWrt Linux-5.4.124
Created: 2021-06-13 22:02:19 UTC
Image Type: MIPS Linux Kernel Image (lzma compressed)
Data Size: 2465658 Bytes = 2.4 MiB
Load Address: 80002000
Entry Point: 80002000
Verifying Checksum ... OK
Uncompressing Kernel Image ... OK

Starting kernel ...

So my guess is something went wrong in assembling the sysupgrade image, destroying the CRC.

I also tried the initramfs-kernel from the bt-homehub and the initramfs-kernel of snapshot for the p-2812hnu-f1, which both gave the same lzma decompress error.

[openwrt-bot]

Mijzelf:

Also tried snapshot sysupgrade. Same result, CRC error.

[openwrt-bot]

abajk:

It looks like a similar issue to [1,2]. The kernel is 2.4 MB large, but U-boot only copies 2MB.

1. https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=c027dbac5a5222e6be4706a7a6a0effefce8ae76
2. https://git.openwrt.org/?p=openwrt/openwrt.git;a=commit;h=23dd7867347ab4fd88592d0bfec1ce5a959c09f3

[openwrt-bot]

Mijzelf:

Yes, you are right. Changing the u-boot environment solved the 1st problem. But that doesn't solve the initramfs-kernel problem. Tried also load address 0x88000000, but that gave the same lzma error.

/Edit: Should have read better. The stock u-boot in this box is exchanged, as it only boots signed images, or something like that. The current u-boot by default loads 2MiB and bootm that. I changed that to 3MiB, and now the CRC error is gone. But the lzma error on the initramfs-kernel still exists, and the same error occurs if I flash snapshot.

[openwrt-bot]

Mijzelf:

Solved. A 'new' u-boot which can extract more than 8MiB target size in combination with the adapted u-boot environment solved both problems.

More about the new u-boot here:
https://forum.openwrt.org/t/zyxel-p2812hnu-f1-u-boot/100281