I experience exactly the same problem, what is more, it seems that ift-load has the 05ac:8300 ID hard-coded into it, so even changing the udev-rule doesn't change anything (my isight webcam registers as 05ac:8507)
reloading uvcvideo gives me the already known output:
[ 247.745593] uvcvideo: Found UVC 1.00 device Built-in iSight (05ac:8507)
[ 247.745605] uvcvideo: No valid video chain found.
[ 247.745643] usbcore: registered new interface driver uvcvideo
@nicolasfdezv
I experience exactly the same problem, what is more, it seems that ift-load has the 05ac:8300 ID hard-coded into it, so even changing the udev-rule doesn't change anything (my isight webcam registers as 05ac:8507)
reloading uvcvideo gives me the already known output:
[ 247.745593] uvcvideo: Found UVC 1.00 device Built-in iSight (05ac:8507)
[ 247.745605] uvcvideo: No valid video chain found.
[ 247.745643] usbcore: registered new interface driver uvcvideo
and trying to manually load the firmware
sudo /usr/lib/ udev/ift- load --firmware /lib/firmware/ isight. fw
gives the following output:
ift-load: USB device 0x05AC:0x8300 not found
ift-load: No iSight found
it seems the loader always looks for the device with the ID 0x05AC:0x8300, whereas the actual ID seems to vary. does this make any sense?
this would also explain why the webcam works after rebooting from OSX - the firmware is already loaded so ift-load isn't needed.
i hope this helps, thanks.