TFTPBoot a sysupgrade image possible from stock?

Hi,

A newbie regarding building firmware for "unsupported" hardware so maybe I am not asking the right questions.

I am trying to install LEDE on my unsupported router (MT7628AN). There is actually a sysupgrade image in the download section, but not a factory to lede image.

Via a serial console I can TFTPBOOT this image and start it using BOOTM. It will decompress the image and boot Linux. After a few seconds it "hangs". Does this mean the image is missing stuff that was suppose to be there in the factory build, or am I using a "corrupt" image?