WRT1200AC can not roll back to OEM fw

Hi, my WRT1200AC installed with LEDE r2443 can not roll back to OEM fw. It can not be updated to any OpemWrt fw either. Such things seemed not happen before r2299. There are some other people around have the same problem as mine. What can I do? Thanks for help!

The error reads: "The uploaded image file does not contain a supported format. Make sure that you choose the generic image format for your platform."

I think this is due to this: http://git.lede-project.org/81b5e8e

Please try running sysupgrade on the command line, using the -F flag.

It worked, thx a lot!