Grandad has bought Apple dev membership.
I'll go against the grain & offer some encouraging advice. First off, if u plan to downgrade. Save ur shsh's with tinyumbrella. Make sure to uncheck "set hosts to Cydia" & "request shsh from Cydia. They're the 2nd & 3rd boxes in TU's advanced tab. If u can't do that then i'd advise u "put the iDevice down, step away from the computer & keep ur hand's where i can see them!" Lol, just kidding, I watch COPS way too much! If that makes sense or u can do it then proceed, if u have any computer sense it's easy.
Step #1. Tell Great grandpa, thanks for the credit card # & to move outta the way! Lol, nicely.
Step #2. Log into dev site & download the appropriate iOS5 firmware file & appropriate iTunes 10.5 for ur scenario. While ur there register ur UDID in the iOS provisioning portal, device section.
Step#3. If u don't have 7-zip or something similar, download it free.
Step #4 Install iTunes 10.5.
Step #5 Unzip the .dng firmware file & then from it, unzip the 2.hfs file. Remember where that .ipsw file is for next step.
Step #6 Backup ur device. Then hold shift when u click restore & choose that .ipsw file. Choose set up as new or from backup, wtvr i've done both with no problems.
Step #7 Have fun, enjoy iOS5 & develop a cool app/tweak then name it after me! Go for it & at the same, do ur part to change the world kid!!!
PEACE, OUT!!!