I have seen how this bug was solved on X10 (it was solved by replacing netd) so I started to search and finally I got it. I have used netd from kuyaDROID. I tested it for one day on Nightly 11 and data works perfectly.
EDIT: Added low in-call vol...
If you want to make it work on custom ROM, you need to modify chargemon.
Here it is for Floyo, FroyoBread and Hackdroid, it should work on other ROMs too, if chargemon is same as in FroyoBread, Floyo and Hackdroid. I tested it on Hackdroid 0.98 a...
NOTICE: This isn't my work. I've just followed this thread http://forum.xda-developers.com/showthread.php?t=963162 to make it work on X8
All thanks goes to zdzihu for xrecovery and offline charging fix and to genyt and weissgold for their guide...
any tutorial will be great:)
Replace vold in /system/bin with file from archive. Set all permissions for this file in Root Explorer.
Thanks to nobodyAtall
Here is ClockworkMod Recovery for FroyoBread. Just install it with xrecovery, but remember that you can't install update.zip-s which are made for xrecovery with this recovery