After Extroot, apk update error

I use the SNAPSHOT version(r28216).

After extrooting, the problem occurred.
I cannot access samba shared services.
apk update fails.

The error message is
ERROR: Unable to read database: No buffer space available
ERROR: Failed to open apk database: No buffer space available
The apk update command failed with code 99.

If I disable and restore extrooting, the above error does not occur.

I am not skilled enough to solve this problem myself.
Can you please advise me ?

Which device ?

Device is Buffalo WXR-2533DHP.

what is the status of free space of ram and rom after errors occur (without disabling the extroot) ?

My Environment

■None Extroot

[Memory]
Total Available --- 317.98 MiB / 464.25 MiB (68%)
Used --- 169.52 MiB / 464.25 MiB (36%)
Buffered --- 1.57 MiB / 464.25 MiB ( 0%)
Cached --- 67.46 MiB / 464.25 MiB (14%)

[Storage]
Disk Space --- 6.00 MiB / 31.13 MiB (19%)
Temp Space --- 5.19 MiB / 232.12 MiB ( 2%)
/dev/sda2 --- 408.71 MiB / 24.90 GiB ( 1%) USB Flash Memory [/dev/sda2]

■Extroot

[Memory]
Total Available --- 315.82 MiB / 464.25 MiB (67%)
Used --- 162.25 MiB / 464.25 MiB (35%)
Buffered --- 1.81 MiB / 464.25 MiB ( 0%)
Cached --- 55.77 MiB / 464.25 MiB (12%)

[Storage]
Disk Space --- 148.83 MiB / 4.00 GiB ( 3%) USB Flash Memory [/dev/sda1]
Temp Space --- 3.57 MiB / 232.12 MiB ( 1%)
/dev/sda2 --- 408.71 MiB / 24.90 GiB ( 1%) USB Flash Memori [/dev/sda2]
/dev/ubi0_2(/rwm) --- 5.87 MiB / 31.13 MiB (18%)

I'm using a custom built image here as a method of installation - does this matter ?

https://firmware-selector.openwrt.org/

no.
just make sure about partitioning and format by following the link-
https://openwrt.org/docs/guide-user/additional-software/extroot_configuration

and also see the swap configuration in that article

Thanks for the advice.
I don't have much time, so I will check back later and give it a try.

When using USB Flash Memory for Extroot, does it mean using it in one partition?
Is it not possible to create and use multiple partitions?
Please point out if my understanding is wrong.

it may be possible with multiple partition
but the file system openwrt should use must be ext2/3/4, f2fs, btrfs, ntfs, or ubifs (note that it can not be a FAT16/32 filesystem)

Thank you for Advice.
(I use f2fs formatting)

Referring to the page I was told about and I was able to Extroot Buffalo WXR-2533DHP using 24.10.0-rc2(r28161).
Thank you for Advice.