I suspect the vignette problem is not really a problem, but a feature: true RAW format brings you just what the sensor spits out. And for a compromise in space and price like any cell phone cam there are real physical problems. Normally the firmware or driver software would correct these things as good as it can, then code result into JPEG with reasonable quality settings. Now you want RAW and with fcamera you get raw data. Raw pixels, just as recorded. You don't want that vignetting? Just take your favorite image manipulation program (The Gimp, Photoshop or whatever) and correct it. (just my 2 cents)