Dear Maintainer,

grub-pc unable to boot from btrfs compressed /boot directory. Removing
compressing flag using 'chattr -c -R /boot' allows system to boot.
Problem does not present on 64-bit systems.

Boot order:

1) Loading Grub...
2) Welcome to GRUB
3) never appear: loading grub.cfg

Full logs:

https://linux-hardware.org/?probe=4e9f8e4c01

Issues is only zstd related. lzo /boot compression works / boots.

I ran btrfs benchmark tests to find out which compression is better for
specified CPU. Turns out this CPU can't handle zstd compression.

File size of 400MB compressing using zstd measuring with 2KB/sec speed
and seems never can finish the job.

# sudo ./btrfs-benchmark
btrfs-progs v6.2

...

    1   992.00MiB  /dev/ram0

    setup:  435MiB 0:01:27 [5,00MiB/s]
[=============================================================>] 100%
     none:  435MiB 0:00:30 [14,5MiB/s]
[=============================================================>] 100%
none 30730ms 14869026/sec 100% (456925184) E:0
      lzo:  435MiB 0:00:43 [9,92MiB/s]
[=============================================================>] 100%
lzo 44995ms 10155021/sec 62% (284934144) E:3822
   zlib:1:  435MiB 0:02:19 [3,13MiB/s]
[=============================================================>] 100%
zlib:1 150413ms 3037803/sec 45% (205955072) E:1668
   zlib:2:  435MiB 0:02:50 [2,56MiB/s]
[=============================================================>] 100%
zlib:2 176573ms 2587740/sec 44% (201863168) E:1444
   zlib:3:  435MiB 0:02:56 [2,46MiB/s]
[=============================================================>] 100%
zlib:3 185409ms 2464417/sec 43% (198782976) E:1392
^C   zstd:1: 30,3MiB 0:01:35 [2,71KiB/s] [==>
]  6% ETA 0:21:10


https://gitlab.com/axet/homebin/-/blob/debian/btrfs-benchmark