After updating my GL.iNet GL-MT6000 to kernel 5.4.238, I realized that the vsftpd plug-in was not installed anymore and I had to manually re-install it.
Is this the expected behavior? I didn't take careful notes, but feel that this happened with some of the previous updates.
This is as expected.
By default OpenWrt wipes the partition, also some files in /etc are also not tracked like avahi, only files in /etc/config are if keep settings is checked, however for config files you still can force preservation by adding the path in config /etc/sysupgrade.conf
It wipes it to ensure OpenWrt can start normally without conflicts with older packages or to safeguard against space.
OpenWrt is designed also on more volatile routers with not much space to avoid bricking and accounting to the actual image upload it wipes the drive.
Hi,
Yes, this is expected behavior.
During a firmware upgrade, the system firmware is updated, so additional packages you installed yourself, such as vsftpd , usually need to be reinstalled after the upgrade.
Our firmware upgrade also mentions this behavior, and you can refer to it here:
Thank you for your understanding.
Thank you so much for the clear explanation and added information:
very good to know, I just try it, hope it works at the next update 
