can cydia SHSHs be accessed after a restore?

[lumina]

This is my first attempt to restore my 3GS...
It went into boot loop a few days ago.
I can put it into DFU mode and iTunes recognizes it, and prompts for a restore.
iReb can put it in a pwned DFU state so I'm hoping to shift-restore.
However, Tiny Umbrella won't recognize it, so I can't save blobs. I do not have any local blobs saved (I did at one point, but lost them in a crash).

I have saved SHSHs with Cydia from 3.1.2 onwards. I'm still running 3.1.2, and backed up in iTunes a few days before this happened (synced with iTunes after avoiding it for a few months and I suspect that's made the phone unstable).

Now for some newbie questions - I'm scared to do anything to my phone in case iTunes leaves me stuck with a reformatted 4.2!

If I shift-restore in iTunes to 3.1.2 with the help of iReb, will that work with no local SHSH blobs?

If I have blobs saved with cydia does that mean I can get them back again (presumably from the cydia server) if my phone gets reformatted? Or did cydia only save them on my phone?

I am wondering if it's possible to (if shift-restore doesn't work) restore to the current firmware and then downgrade to 3.1.2 so that I can apply the backup I made. But this depends on getting those blobs back somehow.

Please help if you can! Thanks!

[iYeow]

close tiny umbrella and try shift + restore again