Step 1. Download Flash for Firefox
Step 2. Extract those files inside the zip file to your
Firefox Portable\App\firefox\plugins\
Lunch Your Firefox Portable and enjoy browsing.
For installing non portable Flash for Firefox
FireFox is a web browser created by Mozilla, the original creators of the Netscape series of browsers. Version one was released in November 2004. Every day, weeks of updates for Firefox version. You can download Firefox for free, download Firefox for windows 7, download Firefox beta, learn to how to download Firefox and install. You can download Firefox plugins and more
Firefox Portable\App\firefox\plugins\
Lunch Your Firefox Portable and enjoy browsing.
For installing non portable Flash for Firefox