Uninstall OpenWRT from Linksys E7350

Installing and Using OpenWrt
1

I am running into a few issues on the snapshot version of OpenWRT on my Linksys E7350 and want to uninstall it till it is a stable release.

What are the instructions for doing so?

2

You can't 'uninstall' OpenWrt on a typical router, as doing so would brick it - you can only install a different firmware in its place (thereby retaining access to the device). How that's done is ideally documented on the device page of your device in the OpenWrt wiki or the git commit adding support for it (again something to be found in the wiki).

Depending on the details of your particular device, these procedures may be difficult, risky and/ or un(der)documented, which is not ideal - but not uncommon either (device support and documentation are user contributed and few users putting in the effort of porting or documenting OpenWrt support for a given device care about reversing the process).

3

The boot loader is one way. The other way is to strip the header from stock firmware and update through OpenWrt. Probably identical to bcm47xx.

4

Short summary is possible and done successfully.

  1. Remove first bunch from the original "FW_E7350_V1.1.00.015_Prod_20210611_code.bin".
    The stock firmware starts with 47 4f 4c 46 (="GOLF") and remove first 32 bytes(I believe).
    Make the first four will be d0 0d fe ed.

  2. Then copy into OpenWRT then use mtd command.

root@AC1750V4:~# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00020000 00010000 "factory-uboot"
mtd1: 00020000 00010000 "u-boot"
mtd2: 00ec0000 00010000 "firmware"
mtd3: 00238d2a 00010000 "kernel"
mtd4: 00c872d6 00010000 "rootfs"
mtd5: 008a0000 00010000 "rootfs_data"
mtd6: 000f0000 00010000 "info"
mtd7: 00010000 00010000 "art"

root@AC1750V4:~# mtd -r write /tmp/E7350original015toMTD3firmware.bin firmware
  1. Then you can access original WebUI at 192.168.1.1. However this method is somewhat partial, I couldn't re-install OpenWRT factory image. Re-flash original 015 image through webUI then will reboot. After that, E7350 is be able to install OpenWRT again.

(4). It might be better to re-flash openwrt itself too. Use sysupgrade command by SSH or thru OpenWRT's WebUI(must be sysupgrade.bin file).