cat bootloader.bin kernel.bin new_rootfs.bin > ps-22a-modified.bin Pad to original size if needed:
grep -r "password" rootfs_extracted/ grep -r "telnet\|ssh\|serial" rootfs_extracted/ Warning: Modifying ps-22a.bin can brick the device. Always back up original. Replacing a file in SquashFS: unsquashfs rootfs.bin # edit files in squashfs-root/ mksquashfs squashfs-root/ new_rootfs.bin -comp xz -b 256K Rebuilding full firmware: Concatenate modified parts: ps-22a.bin
modprobe mtdram modprobe mtdblock dd if=rootfs.bin of=/tmp/mtdfile losetup /dev/loop0 /tmp/mtdfile mount -t jffs2 /dev/loop0 /mnt If unknown custom format – check for CRC , TABLE headers, or use firmware-mod-kit : cat bootloader