About year ago I got my first Blackberry device. Of course I did some research of what we can do with it. I mean of course, more than RiM allow us to do.
First I’ve got my phone debranded. That involves uploading branding file to device. When I did that, I started to wonder if I could edit or create my own branding file with my own splashscreen image or other data changed. I found some VSM file format description (but incomplete). I did my own research (including software disassembling) and finally I created VSMTools. It’s an easy-to-use command line tools which allow you to extract, edit or create your own VSM file.
vsmtools06.rar is my tool to extract, edit and create branding VSM files. I’ve also documented VSM file structure. I got it all except sign section. VSM files are digitally signed and as far as I know it is done by RSA-SHA1 private key and the public key (which I covered in this document). It is used to check the file integrity. I can’t tell any more about the sign mechanism, if you do have any information about that, please contact me. Sign section may be not present in VSM. Blackberry 8800 accept unsigned files, but maybe some newer devices don’t.
Some usefull links related with VSM files: topic about hacking VSM files on GSM Forum, VSM resources description in BlackBerry API.