It is absolutely possible to overwrite the operating system. You have full root access when you log in. You can dd right over the flash device /dev/mtd0 with wh

It is absolutely possible to overwrite the operating system. You have full root access when you log in. You can dd right over the flash device /dev/mtd0 with whatever you want. As to framing me, well... I don't think it's much easier than framing me using some other method. And I think the cross section of people that want to frame me, and people who know how to compile Linux, is hopefully very small.