[OpenWrt Wiki] Image formats
https://openwrt.org/docs/techref/image.formatext4 This firmware contains a regular ext4 Linux partition. Mostly used in x86 and x86_x64 systems. squashfs This firmware contains a type of partition that is compressed and mounts read-only. All modifications (file edit, new files, deleted files) are committed to an overlay. .bin/.chk/.trx See also TRX vs. TRX2 vs. BIN initramfs
[OpenWrt Wiki] Upgrading OpenWrt firmware using LuCI and CLI
openwrt.org › docs › guide-userUpgrading OpenWrt firmware using LuCI and CLI * Related pages: * Flash Layout: provides background on how OpenWrt uses device storage space * Upgrading OpenWrt firmware using CLI * Upgrading OpenWrt firmware using LuCI * Keep Settings and Upgrade Compatibility How the OpenWrt upgrade works An OpenWrt sysupgrade will replace the entire current OpenWrt installation with a new version.
[OpenWrt Wiki] Raspberry Pi
openwrt.org › toh › raspberry_pi_foundationRaspberry Pi The Raspberry Pi is a single-board computer without an Ethernet Network Switch. There are many more Single-board computers without one. Raspberry Pi 1 and Zero support only soft-float (armel) which is slower than hard-float. Raspberry Pi 2 and 3 is compiled with the ARM hard-float kernel ABI (armhf), this means that non-integer math is done in hardware instead of in software ...