Rockbox

When does the shutdown happen? Is it during intense disk activity? Is the disk still spinning when the shutdown happens? Does the iPod charge very slowly in Rockbox compared to in the original firmware?

I guess you are talking about USB charging, and I expect FireWire charging does not have this problem.

I don't have my iPod here now, so I can't test all the things you wrote, but it happens when using USB wall charger

I think I can vouch for this as well. I currently have r20820 on my iPod but I firmly believe this has been a problem since before 3.2, maybe even 3.1. I'll leave my iPod booted into Rockbox, plugged into a AC adapter and the battery actually discharges to nothing until the device shuts down. But the frustrating part is that the iPod turns back on since it think you just plugged in the AC adapter, but it has almost 0 power so it shuts off. It continues this process throughout the night while I sleep. It's happened more than twice and it's pretty annoying. Not only will it do the above but the remaining time and percentage seem to be messed up after plugging in the AC adapter. Also, after I unplug the AC adapter (when there's still battery life and it's still booted into Rockbox) it thinks I just unplugged the USB cable and flashes the USB image.

Just noticed that the poster has a 4G Color, so do I. Or, rather a "iPod Photo".

I have the same problem as spanky. I plug it into my computer and when I try to sync after about 5 min battery fully discharges and then iPod keeps rebooting. I can boot into he original iPod firmware and it will say battery is really low and go into charge only mode for a while. Then I can sync with the original IPod firmware.
I read about this problem here http://dreamlayers.blogspot.com/2008/12/video-ipod-wont-charge-via-usb-wont.html But I can still charge in IPod mode and Rockbox. Just seems to happen when there's intense disk activity, which leads me to believe it's using more than 500ma and not using USB power for excess activity.

Please see http://www.rockbox.org/wiki/WebHome?topic=TargetStatus . ipods from 4th gen, color/photo, and 5th gen, video, do not have good power charging in rockbox yet. It is a known issue (with no solution as yet, as far as I know). I think it's always been an unresolved issue (not just something since 3.1). For now the recommended solution has been to charge using the original firmware.
I'll leave this bug tracker open .. since it is a bug and the workaround is unpleasant ..

This is still a problem. What happens is if the battery is totally drained the original firmware goes into low power charge mode to get some power on the device. If left on its own it will boot into rockbox when done, find that it is charging from the wall start charging but also recognize that it is very low power and shut off. Then it again recognizes it is plugged into the wall and turns back on. It then recognizes its very lower power and shuts off. If this cycle uses up enough power it goes back into original firmware lower power mode and charges a bit then the cycle begins anew.

Hi All, same problem here: when battery is totally empty and connected to USB charger on the wall, first the apple appears, then Rockbox boots and runs for one to two seconds, then shuts down. This is pretty annoying since one can hear the disk stopping repeatedly, but mainly because it does not seem to charge. Connecting it to a computer starts the usb mode, and Rockbox just starts correctly, and the iPod charges, but as it's a 80GB model, I already have everything I want on the iPod and do not want to use a computer only for charging it…

I usually just boot in apple mode with the lock switch on and it will charge. I use it that way to sync on the computer too, because it will sometimes reboot randomly in rockbox mode. I hope that makes sense, because I don't know the specific terms.