Downgrade RouterOS from 6.40.5 to 6.38

RouterOS General
1

sxt aq lite 5 a new one,downgrade doesn’t work rebooting after putting the routeros 6.38 in files via winbox doesn’t work too

2

Have you tried /system package downgrade ?

https://wiki.mikrotik.com/wiki/Manual:System/Packages#Downgrade

[admin@MikroTik] > /system package downgrade
Router will be rebooted. Continue? [y/N]:
3

You cannot downgrade below the version that comes with a device. When your new device came with a newer version than 6.38,
you cannot downgrade it to 6.38. The minimal version is listed in system->resources.