[OpenWrt Wiki] Filesystems
https://openwrt.org/docs/techref/filesystemsThe flash.layout article documents how OpenWrt uses both SquashFS and JFFS2 filesystems combined into one filesystem by overlayfs. The kernel is also stored separately from these partitions in raw flash. When the kernel is built, it is also compressed with LZMA and gzip, as documented in imagebuilder . Boot process
[OpenWrt Wiki] The OpenWrt Flash Layout
https://openwrt.org/docs/techref/flash.layoutIt also includes default configuration files used when booting into OpenWrt Failsafe mode. It does not contain the Linux kernel. All files in this directory are located on the SqashFS partition, and thus cannot be altered or deleted. But, because we use overlay_fs filesystem, overlay-whiteout -symlinks can be created on the JFFS2 partition.
[OpenWrt Wiki] Image formats
https://openwrt.org/docs/techref/image.formatPreviously known as trx image, sysupgrade is designed to be flashed from OpenWrt/LEDE itself 2). Commonly used when upgrading. Specific formats ext4 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.
FS#4100 : SQUASHFS errors with OpenWrt 21.02
bugs.openwrt.org › indexOct 20, 2021 · FS#4100 - SQUASHFS errors with OpenWrt 21.02. - Software versions of OpenWrt/LEDE release, packages, etc. I installed openwrt-21.02.0-ath79-generic-wd_mynet-n750-squashfs-sysupgrade.bin on a Western Digital My Net N750 that had been running openwrt-19. The router seemed okay initially but after power cycling, it started reporting errors:
[FS#4100] SQUASHFS errors with OpenWrt 21.02
lists.openwrt.org › pipermail › openwrt-bugsOct 20, 2021 · THIS IS AN AUTOMATED MESSAGE, DO NOT REPLY. A new Flyspray task has been opened. Details are below. User who did this - crowston (crowston) Attached to Project - OpenWrt/LEDE Project Summary - SQUASHFS errors with OpenWrt 21.02 Task Type - Bug Report Category - Base system Status - Unconfirmed Assigned To - Operating System - All Severity - Low Priority - Very Low Reported Version - Trunk Due ...
[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)!