Well, there is
the original image. To restore it you would need to burn it instead of new_opt.900.img. You may want to unpack it, re-pack it again (so it isn't as big) and generate the MD5 checksum (new_opt.900.md5).
The latest Russified images (
1.05a) allow setting the timezone to pretty much any offset (via the special config interface in the About Reader screen).