OpenWRTでは、普通のLinuxのように /etc/fstab に書き込んでもだめみたいである。

https://openwrt.org/docs/guide-user/storage/fstab

root@OpenWrt:~# cp /etc/config/fstab /etc/config/fstab.ORIGINAL
root@OpenWrt:~# mv /etc/fstab.ORIGINAL /etc/fstab
root@OpenWrt:~# block detect | uci import fstab
root@OpenWrt:~# cat /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 '/mnt/sda1'
	option uuid 'db4b6bad-fcf4-d760-af61-80fe2f42ca1e'
	option enabled '0'

config mount
	option target '/mnt/sda2'
	option uuid '133d7fd3-0120-9fbf-5004-cb32421736b5'
	option enabled '0'

config mount
	option target '/mnt/sda3'
	option uuid 'bee41517-55b3-802c-f940-4605bc06b2d9'
	option enabled '0'

config mount
	option target '/mnt/sdb1'
	option uuid 'db4b6bad-fcf4-d760-af61-80fe2f42ca1e'
	option enabled '0'

config mount
	option target '/mnt/sdb2'
	option uuid '133d7fd3-0120-9fbf-5004-cb32421736b5'
	option enabled '0'

config mount
	option target '/mnt/sdb3'
	option uuid 'bee41517-55b3-802c-f940-4605bc06b2d9'
	option enabled '0'

config swap
	option device '/dev/md2'
	option enabled '0'

config mount
	option target '/mnt/md3'
	option uuid 'eddcf2be-32f6-4be7-9c58-85dccafcf382'
	option enabled '0'

root@OpenWrt:~#