Change installation from /opt to /usrdata/opt There is more room to work with at /dev/ubi2_0 which is where /usrdata is mounted from. From stock firmware ubi0 (rootfs [/]) only has 49.3 MBs free while ubi2_0 has 119.8 MBs
Forked from https://github.com/Entware/Entware/wiki/Install-on-Android#installation Orginal: https://bin.entware.net/armv7sf-k3.2/installer/alternative.sh