Lamobo R1 Exroot Fails

Hello there! I was tring to follow the official instructions in order to expand the overaly. I installed the distro in a 8 gb sdcard. I created a fourth partition mmcblk0p4, and formatted it as f2fs. The overlay copy and mount worked like a charm, and when I create tis /etc/config/fstab:

config 'global'
option anon_swap '0'
option anon_mount '0'
option auto_swap '1'
option auto_mount '1'
option delay_root '5'
option check_fs '0'

config 'mount'
option target '/overlay'
option device '/dev/mmcblk0p4'
option fstype 'f2fs'
option options 'rw,sync'
option enabled '1'
option enabled_fsck '0'

config 'mount'
option target '/mnt/mmcblk0p1'
option uuid '6088-5ACB'
option enabled '1'

config 'mount'
option target '/mnt/mmcblk0p2'
option uuid 'e24f9140-a8faa5d7-66c2abda-c9fea865'
option enabled '1'

I got the /dev/loop0 mounted as overlay, with this error:

[ 7.497531] block: unable to load configuration (fstab: Entry not found)
[ 7.504277] block: no usable configuration
[ 7.509332] mount_root: switching to f2fs overlay

Any ideas would be most welcomed, thanks!