First, 1001 thanks to the Rockbox team for creating such a great free product. I'm fairly new to Rockbox. Hated it during Week 1 and couldn't live without it starting with Week 2.
Background: Mine is a Sansa Fuze family. The four of us collectively have 9 Fuzes (the older superior models) and 5 Altec Lansing docks. Of the 9 Fuzes, 7 employ Version 2 firmware. As luck would have it, I happened to install Rockbox on one of the two Version 1 players. Worked fine on the docs as well as via USB ports in our car stereos. Then, I installed RB on a V2 player and then eventually trying three other V2 players. In each case, Rockbox would not play through a dock or USB; however, when I booted up the Sansa firmware, it would play fine. So, this seems to be a Rockbox issue.
If at all possible, my family and I hope this issue can be addressed with your next update. It has been difficult to locate V1 players for sale on eBay and Amazon. Plus, we'd love to be able to use our now-dormant 7 V2 Fuzes.
Thanks again for all that you do.