I tried flashing my own OpenWrt build (picked https://github.com/openwrt/openwrt/pull/12104 and build against f30757b94e6f0b0a547b4932eb97e550f0bffe3d on master) on my MR70X earlier and it said firmware upgrade success after which the page pretty much reloaded instantly and nothing else really happened I tried restarting and resetting the router but it appears to only boot into the web recovery mode.
I tried the following things:
use a different browser (ungoogled chromium > firefox)
At this point I'm kinda out of idea's and options for as far as I can tell, someone recommended me to check the serial output but I don't have the required equipment nor the knowledge to do so and I also don't have a flasher so if anyone has any suggestions feel free to let me know
In recovery mode GUI You can only flash openwrt-ramips-mt7621-mercusys_mr70x-squashfs-factory.bin . To check if file was delivered You might use ethernet status byte counts
Then after boot to OpenWrt ssh -l root 192.168.1.1 should be possible.
If the openwrt-ramips-mt7621-mercusys_mr70x-squashfs-factory.bin was sent to recovery GUI correctly and nothing more happens than without serial console we can only guess.
Guide to use dir-853-r1 fw require serial console and flashing breed bootloader. Let's keep the PR#12104 way
I'll try looking at the network stats while flashing it and I'm aware i should flash the factory bin but then again regardless of when I flash stock or openwrt it won't boot into anything else but web recovery and it always skips to look like 40%
alright I found one I can pick up in a couple hours. just wondering do i have to solder these or can I just connect the cables? I also have no idea how to open up the router I remove the two screws already.
no solder is needed if you can keep it connected for few minutes . J1 is serial 115.2k in 3.3V standard .Connect Pin 1.TX (pointed by small triangle) 2.RX 3.GND . Putty can be used to connect to serial console
Did you try renaming the firmware file to a short name before using it. I personally had problem with the recovery UI upload not working on this model unless the file name was shorter than 8 characters. Ok, scratch that, I just noticed you mentioned it.