Tired of manually keeping the flashplayer.xpt and NPSWF32.dll files synchronized between your system directory and your Portable Firefox directory? If you're running Windows Vista or later, symbolic links can help.
From an elevated command prompt:
CD {portableappsroot}\FirefoxPortable\App\Firefox\plugins
{kill any running Firefox instances}
del flashplayer.xpt NPSWF32.dll
mklink flashplayer.xpt %windir%\System32\Macromed\Flash\flashplayer.xpt
mklink NPSWF32.dll %windir%\System32\Macromed\Flash\NPSWF32.dll
I've tried this with Firefox 3.6.4 running under Windows 7 (all 32-bit), and it seems to run perfectly fine. I haven't tried under 64-bit Windows yet, but it would likely require replacing "System32" with "SysWOW64" above.
Of course, your mileage may vary. There may be reasons why you'd want to keep these independent and update separately.
Isn't that assuming that Flash is actually installed on the PC you're working on? More than that, isn't is assumuing that it is in a specific place (many windows installs use a different folder for windir - especially dual boot or upgraded machines.
Also, doesn't it only work if your flash drive is formatted NTFS, which most such drives aren't?
It does indeed require NTFS on the volume holding the portable apps. This is true in my case (HD) but, as you mentioned, not necessarily true for flash drives.
Regarding the system location -- while it may theoretically be possible to change the Windows installation root, the default is C:\Windows. Earlier versions allowed you to change the installation directory, but I don't think modern versions allow this. Also (IIRC) the system volume is always mapped to drive C: regardless of partitioning.
It may not be universal, but I suspect it will work 99.99% of the time.
It should be noted that setting symbolic links requires admin rights on Vista and above.
Sometimes, the impossible can become possible, if you're awesome!