twrp.fstab

# mount point fstype device options (length for cryptfs encryption footer)
/boot		mtd	boot

/data 		auto	/dev/lvpool/userdata 	length=-16384 flags=backup=1;canbewiped;wipeingui;wipeduringfactoryreset
/cache		yaffs2	cache				flags=backup=1;canbewiped;wipeingui;wipeduringfactoryreset
/system	ext4	/dev/lvpool/system		flags=backup=1;canbewiped;wipeingui

/external_sd	vfat	/dev/block/mmcblk1p1	 /dev/block/mmcblk1	flags=display="External SD Card";storage;wipeingui;removable