For those of you iPHONE users still having trouble with the AV cables, try these (link below). I bought them from ebay and they actually work with the new firmware. Plays perfect through the nav screen and looks good on the big screen. Keep in mind that they are not the Apple Composite AV Cable MB129LL/B. Not sure what the differance is but I do know that these work (A1258). $26.50

• Original Apple composite AV cable (A1258)
• Support iPhone Firmware 3.0/3.01/3.1 and up!
• Qty: 1
• Enjoy videos, photos, slideshows and music on your big screen TV.
• High quality stereo sound output supported.
• USB cable included and enable you to charger your device or sync with your PC/Mac.
• Length: 6ft

Compatible with:

• iPhone3GS 32GB 16GB
• iPhone3G 8GB 16GB
• iPhone 2G 4GB 8GB 16GB
• iPod touch 2nd Gen 8GB 16GB 32GB
• iPod touch 8GB 16GB 32GB
• iPod 4th / 5th generation/ iPod Photo/ iPod Video
• iPod Classic 120GB
• iPod Nano 3rd/ 4th/ 5th Generation

Ebay Link: Original Apple iPhone 3G 3GS iPod Composite AV TV Cable - eBay (item 220530613045 end time Jan-22-10 03:01:43 PST)

 

Is there any way to make the old Apple AV cable work without downgrading the firmware?

 

Not sure. It wuks for some and not for others.