I myself messed up my Tp-Link TD-W8968 which i bought in 2018-2019 it was ver.4 hardware ADSL router with usb. I tried openwrt for testing out of curiosity just for knowledge. But when tried to rollback to OEM stock firmware. The error was Image uploading failed. The selected file contains an illegal image. I googled and found this topic https://forum.openwrt.org/t/solved-need-your-help-to-revert-tp-link-td-w8968-v3-firmware/31942 - in brief what this link has is, the similar issue was solved by stripping bytes from .bin firmware and that worked as upgrade firmware, but the file was of ver.3 firmware and it was too old like 2015 something. I checked Official TP-Link site for TD-W8968, there latest one was ver.5 and i wanted that as firmware on my device. So i looked up for how to strip those bytes from .bin file of firmware and found this link https://forum.openwrt.org/t/stripping-firmware-how-much-to-remove/33670/6 Just for record ...
