SharePoint Short #8
It’s easy to extract and make changes to a WSP file – use any compression program (WinZip, WinRAR, etc.) to extract it to your machine and you’re good to go. Once you’ve made your changes to the content, you can’t use the same compression tool to re-create the WSP. Also, to use the Makecab command line utility requires a DDF file, which won’t be part of the original WSP, so you’d need to re-create this. There are tools out there for doing this, or if it’s a reasonably small WSP you could do it manually.
A better solution for this type of scenario is to use a free tool like IZArc. Although similar to the other compression programs, this one also allows you to create CAB files, which after you rename to WSP you are able to deploy the updated solution.