Hi can any
body help. after upgrading my BThome hub 5A from previous version 19.07.04 of working openwrt to 19.07.07 i cant save any config or first boot password change. loses settings every time i reboot.
device has 128mb ram and flash
That would be an issue with your particular installation/ device, not the BTHub5 in general (which works just fine). Before digging much deeper, I'd suggest to do a fresh new upgrade without keeping settings (19.07.7 or 21.02.0-rc1; let the device 'rest' for about 5 minutes after the flashing and before trying to log in) and debugging in a dedicated thread from there on.
This thread is about devices with insufficient amounts of flash (4 MB), which just manage to build in 19.07.x, but no longer have enough free space for the overlay (while you would have over 100 MB at your free disposal, if everything worked out).
Having reinstalled the previous upgrade 19.7.07 the config save problem is resolved. just to check i installed the latest snaphot on top and the problem comes back. there may be a problem with the snapshot?. is it possible there is an issue with partition size or something as /dev/root shows 100% and 0 % available.
Also i'm relativley new to openwrt so is it possible to resize root on the fly as with Linux.