Switching from optware to entware it's easy, for arm routers:
1. save optware.arm folder if you want to go back later
Code:
mv /mnt/sda1/optware.arm /mnt/sda1/optware.arm-backup
2. install entware (starting with firmware 378.51-beta1 script is included) or for older versions
https://www.asuswrt.eu/how-to-install-entware-arm/
3. install desired packages with opkg command instead ipkg
4. restore some conf files from optware.arm-backup to entware.arm directory, ex. lighttpd.conf, pyload.conf...
If you want to switch back to optware, rename entware.arm folder to entware.arm-backup, delete post-mount script, rename back optware.arm-backup to optware.arm and reboot router.
Warning!!! If you installed chrooted debian inside optware or entware, be sure ext_dir is not mounted to avoid deletion of media files.
I recommand ENTWARE