Some simple things to take care of:
mtk_uartboot is the only process opening the UART -- if you forgot to close minicom or putty or any other process which still got the same UART open it won't work.mtk_uartboot while the device if switched off. Then power on the device while mtk_uartboot is running.Unfortunately I had made sure I did all three of these things already but had no success.
Currently using my MacBook Pro, perhaps I should go and dig out an old Linux computer and try with that?
You guys are geniusus.
Thank you.
okay, this is user 101
I'm at the point where it boots and runs fine apparently as an AP
however after flashing I dont think I have LUCI installed as 192.168.1.1 doesnt respond
after flashing the sysupgrade what step(s) should I perform to get back to a standard latest release with LUCI?
Thanks so much for fixing this.
EDIT:
I ran opkg update
and opkg install luci
from shell and I got luci back
Worked perfectly with an old Linux laptop running Ubuntu ...
Perhaps an interesting thing to know? Definitely a voyage of discovery for me!
New problem is that whilst I can now see my router has booted I can only see it through the serial cable.
Having connected through the serial cable to get to the console I can see that it is running the 6.1.78 kernel, but my ethernet connection is doing nothing.
A brief look at "dmesg" suggests that the kernel hasn't found eth0
I saw this at one point too.
I did a factory reset thru the uboot menu, and it yielded a fully functional wan and lan ports
(however, after that, the web page at 192.168.1.1 isnt responding, yet I have a DHCP address on my Ethernet and that is my default gateway and Internet works.
Ok, I managed to factory reset as you suggested, and with my own home rolled firmware I automatically configure a suitable wireless AP which then appeared.
I can now login to the router over WiFi and Luci is working for me, but the ethernet devices still aren't working.
I tried it on my friend's MacBook with CH343. It doesn't work with the USB-CDC mode in Mac and it only works after I installed the vendor serial driver from WCH.
Anyway I'm glad that the Linux version works fine for you 
As for the ethernet issue, could you check if the eeprom data onboard is correct or not? for example does your WiFi have a correct MAC address?
I'm wondering if you are using the latest snapshot where everything is in UBI, without going through the installer to move eeprom data.
so... I ran opkg update
and opkg install luci
from shell and I got luci back
@daniel Hello Daniel, thank you for the updated installer. I tried to build the UBI Installer from your github repo "main" branch but I am seeing an error https://github.com/dangowrt/owrt-ubi-installer/issues/172 . Not sure if I am doing something wrong.
Also, does this commit https://github.com/dangowrt/owrt-ubi-installer/commit/9745076a8d29fdc88495156af46cee4db84f68f0 mean we need to update the recovery image stored in the device?
Yes, I am using the latest snapshot, and I haven't used the installer yet. I assume my next step now that I have something that boots?
I assume I need to download some sort of installer image that is possibly listed earlier in this thread and then once I flash that use that to flash the snapshot?
I was trying to get some kind of networking to allow me to upload the firmware that I need to flash. I can probably do that over WiFi now that is working.
Really appreciate all the help with this, it will teach me not to be so cavalier!
Thanks,
Michael
ERROR: BL2: Failed to load image id ...
(never mind the actual image id)
Then please help and use mtk_uartboot to gather some crucial information needed to debug this issue. @hackpascal sugested to use bl2 with increased loglevel on a bricked device to see what's going on there. So if your device is currently in this condition, you can help by doing this using the special bl2 image the installer now builds for this purpose: https://github.com/dangowrt/owrt-ubi-installer/releases/download/v1.1.1/bl2-for-debug-snand-issue.bin
./mtk_uartboot --brom-load-baudrate 115200 -s /dev/ttyUSB0 -p bl2-for-debug-snand-issue.bin --aarch64 ; screen -h 10000 /dev/ttyUSB0 115200
You will then see a lot of debugging output in screen and the result should be the same, BL2 fails to load the image, just now we may know why.
Once no more output arrives, please share the complete content of the screen buffer for further analysis.
I downloaded openwrt-mediatek-mt7622-linksys_e8450-ubi-initramfs-recovery-installer.itb and flashed it using the firmware I had installed, after doing that it still doesn't boot without using mtk_uartboot.
Now when I do boot it with mtk_uartboot I don't have any networking (wifi or ethernet) and I see more errors during the boot process.
Is there something else I should be doing?
Do you want me to use the bl2-for-debug-snand-issue.bin?
Thanks,
Michael
You need to run the installer, not flash it. If your device has a working bootchain, that would be the same, after flashing it, it would run it after a reboot. However, as your device doesn't have working bootchain, flasing the installer won't work.
Loading it via TFTP in U-Boot is the easiest way to do this if you don't want to flash back the stock firmware.
Actually, by flashing it, you probably permanently erased the calibration data and MAC addresses which means that those now need to be cloned from a donor-device before you will be able to use it in any way.
I seem to just keep on digging deeper and deeper into problem territory. Fortunately I have two other fully functional RT3200 routers at my disposal, so it should be possible to clone one of them if you could possibly point me in the right direction?
I will dig around and try to find the instructions on how to TFTP in U-Boot, definitely no interest in going back to the stock firmware.
Thanks,
Michael
@daniel is there a method to verify the wifi calibration data is correctly stored on a unit that has been e.g. bricked-and-restored?
Is WiFi-works-fine proof enough?
I have the debug output saved to a text file. I'm new to this forum and it doesn't look like I can attach it. Should I just copy into a post?
Check the WiFi MAC addresses. If they are correct (ie. +2 and +3 of the address written on the stick on the bottom of the device) then everything is fine.
Perfect, they are correct. Thanks again 
You’re a hero for getting this data. You could just upload text file to site like this: