Using serial recovery I was able to completely boot up the router. (Wifi and luci while regular on and of switch dose nothing)
The guide in documentation says use TFTP to flash preloader and go from there but since but time to trigger bootloader options is slower than I manage to launch putty, its mid way booting before I see it.
Hold off on this... use 23.05.5 if you're doing this right now. 24.10.0 has not yet officially been released (it'll probably be soon, though). The reason to avoid it at the moment is that, until it is officially announced, we don't know if there could be any specific issues with the build.
Not in my experience. If the com port is claimed by putty then mtk_uartboot can not establish the connection because only one thing can be connected to UART at same time.
I am not sure if all those steps are strictly needed but this seams like good path for me to follow.
I was a little foolish earlier and used the beta version that messes with UBI partitions, so I think I should be using 24.x partitions are setup for it.
Success! Router now boots on flipping the power on button. Not sure if OKD will not return in the future but for now it seams stable enough.
Here is the processes I followed:
Boot the router up by using serial recovery like described the docs: https://openwrt.org/toh/linksys/e8450#recovery_steps
Just let it complete the boot sequence to get the full OS loaded up instead of trying to flash new firmware over TFTP.
(Small fix: for powershell symbol to make commands execute sequntially is ; not &&)