In some scenarios, it may be noticed that OpenWrt does not expand to occupy the entire eMMC flash on the Gateworks SBC. There is a configuration parameter that OpenWrt has set.

The 104MB comes from OpenWrt's CONFIG_TARGET_ROOTFS_PARTSIZE config if you are building OpenWrt yourself.

Otherwise if you are trying to resize an already-installed OpenWrt there's an OpenWrt wiki article that provides an example here: ​https://openwrt.org/docs/guide-user/advanced/expand_root

We verified it works just fine; The wget for the automated install section may not work, but you can install the necessary packages and cut-and-paste the script then reboot.