[OpenWrt Wiki] Filesystems
https://openwrt.org/docs/techref/filesystemsOpenWrt does not use other filesystems as rootfs. It supports several filesystems attached to via various mechanisms like USB, SATA or network. For a list see storage . mini_fo was used by older OpenWrt version and thus there are still references to this in the Wiki replaced by OverlayFS now. The mini_fo filesystem on LWN.net
[OpenWrt Wiki] Filesystems
openwrt.org › docs › techrefSquashFS is a read only compressed filesystem. While gzip is available, at OpenWrt it uses LZMA for the compression. Since SquashFS is a read only filesystem, it doesn't need to align the data, allowing it to pack the files tighter thus taking up significantly less space than JFFS2 (20-30% savings over a JFFS2 filesystem)!
OpenWRT Read-only file system - IT Support
www.2hf.org › openwrt-read-file-system-84Feb 19, 2017 · OpenWRT Unsaved Changes. The system can’t write to the disk. Also we can’t install any tools to check the file system. Solution OpenWRT Read-only file system: Create a backup from you System ( System – Backup / Flash Firmware). Then remove the SD card from your Banana PI and flash the OpenWRT again! There is now way to fix the problem ...