@rbbcpa: Not sure, since the 2.3 hacks packages used an exploit which has been plugged since. You'd better ask for someone to repackage it properly for v2.5.
And, more specifically, if you're talking about ebs' screensavers timeout hack, check
https://www.mobileread.com/forums/sho...9&postcount=59 .
The jailbreak in itself (at least this one and clarknova's) won't block auto-updates, no, but other hacks might. (the timeout hack does, for example, while these fonts/ss/usbnet hacks are update-safe).