Jailbroke 3G 3.1.3 with jailbreakme primarily for tethering to macbook. Had all working fine, then like an IDIOT got into downloading custom themes before more important things like open ssh, and no installer. Now, Cydia crashes on opening. If I do a restore in itunes, will bring me to 4.2 and don't want that... have no backup of 3.1.3 or other previous... downloaded cyberduck and tried to connect, but probably failed because I don't have open ssh. Did searches on getting Icy without Cydia, but don't have the aps I should have downloaded in the first place before playing with themes. I COULD KICK MYSELF. Is there anything I can do to get Cydia or Icy or ssh to access my root files that are crashing Cydia??? Thank you....

FYI, all alternate package managers besides Cydia (Rock, Icy, Installer) have been gone for a loooooooooooong time. The only one that works right now is Cydia -- none of the others are active anymore or even functional.

Since you're on a 3G, you don't have the SHSH requirement to get to 3.1.2 and can restore 3.1.2 in DFU mode as often as you'd like without any problems -- just make sure you're doing a shift-restore.

If I were you, here's what I'd do:

1) Make a backup of your existing iTunes mobile backup.
2) Plug the phone in and make a new backup.
3) Make a back-up of the new iTunes mobile backup.
4) Shift-restore the phone and point to the 3.1.2 IPSW
5) After restore, let the phone activate in iTunes.
6) Tell iTunes *NOT* to restore from backup, but to set up as a new phone.
7) Sync all of your data back to the phone.
8) Use redsn0w to jailbreak the phone.

You should be set at 3.1.2 with Cydia, jailbroken, and with all of your contacts and apps and data. If you want your SMS history or Call history, install OpenSSH and extract the databases from the backups you saved in step 1 or 3 and overwrite on the phone, then reboot.

Good luck!

Thank you SO MUCH for your reply and instructions. It worked like a charm. This time, I downloaded necessary apps from Cydia first, instead of playing... that was my first jailbreak and I am a novice and learning. Sometimes it's hard, when you're in a jam browsing through all the pages... you don't know what's out of date or what is really going to work.
But your suggestions worked!
I really appreciate your advice--- it helped! And thank you for having this forum for the community.
--Liz

Glad to hear it worked! Let us know if you have any other questions, and as always, if you've got a few bucks spare and want to contribute, feel free to donate by clicking on the donate links in most mods signatures or on the main page. (Sorry for the shameless plug! )