Upgrading to iOS 5.0 from 4.x jailbroken - Can I use iTunes directly to upgrade?

[Drummerboybac]

Hi all, I am preparing to upgrade my JB 4.2.1 iPhone 4 to iOS 5. I understand that there is not untethered jailbreak currently available, and I accept that I will lose my jailbreak until a new untethered jailbreak is available.

My question is this. Does clicking the Update button in iTunes do a backup and restore on the iPhone 4? I noticed that it did that on my non-JB iPad 2.

If it does in fact do a backup and restore, then does that mean that I can just use the Update button in iTunes to upgrade without losing a portion of my internal storage space like used to happen in older firmwares?

[MagicCowInUse]

I just clicked update, as I do with every update. I do this because I personally prefer a fresh clean version of the OS to work with and start new every new firmware I decide to update to.

My information did actually back up and was restored to my phone when completed. But I did notice a TON of bugs when I was trying to tinker. iTunes would not download any apps without "accepting" new user agreement, which it kept trying to bring me to but would never load.....and on and on...

I would suggest just doing a complete restore and start new.

[drjerryk]

I had to put my jailbroken iPhone 4 in recovery mode. I then did a complete restore.

[rest_easy]

just an FYI, Restore is better than Update.

Yes, you can just upgrade. sync first then do that. If you restore you can then restore from backup at the end which will put all your junk back on.
Just be warned that sometimes using a jailbroken backup can cause an infinite reboot loop. If this happens then it happens. You can pull some info out of the backup or backup in other ways (appbackup in cydia, using ssh or ifunbox etc. I've written up somewhere the harder way to backup which may be a bit dated).
itunes backup isn't always that great and can generate errors so if you see something funky don't be too quick to blame ios5 or new hardware or the jailbreak.

But if it works it works.

[Drummerboybac]

Thanks for all the input. Not restoring from backup at some point isn't really an option for me, due to how much is set up on the phone. Since I use very minimal mobile substrate( just sbsettings and weathericon), It works ok for me.

I guess my question more centered around whether I was going to permanently lose disk space, by clicking update in iTunes. I went for it, and it looks like iTunes' update process does do a backup, restore to 5, then restore from backup, which is the method I would BAC used anyway. It seems that if you want to minimize problems from this approach, I would disable the mobile substrate tweaks beforehand, or just uninstall all your cydia stuff then reinstall after upgrade.

Either way, I'm good to go now. Thanks again for all the responses