Thank you for contacting us.
First, I would like you to send me a troubleshoot file. Access router's WebUI, go to System -> Administration > Troubleshoot section and download troubleshoot file from there.
Next, I would like you to attach a screenshot of the SSH command hexdump -C /dev/mtd1 output.
There is a likelihood, that we will need to arrange a remote session via Anydesk for me to access your device, but before that I would also need a serial number of your router.