Hi,
i've found a solution for preview image problem in mag 322, reverting firmware to old working version:
Download file 2.20.05-324 (December 27-2017) imageupdate from:
http://fw.tivi.bg/im/322/imageupdate
save it to a folder named "mag322" in your usb drive (fat)
put your usb drive in mag
Open Settings⇒ System settings ⇒ Software update.
In Software update window set Update method = USB
Select Verify (OK) to make sure that STB can detect imageupdate file.
If the file is detected and readable successfuly you'll see Software Update window
for more details follow the instructions in:
https://wiki.infomir.eu/eng/set-top-box/stb-linux-webkit/mag322-324-349-351/software-update-mag322-324-349-351
you're welcome