Downgrade then re-jailbreak??

[brk1]

I have just got hold of a 2nd hand 3GS 32 GB phone that was on 4.2.1 firmware, JB'd it with Greenpo1son RC 6.1 without problems. I have checked for saved SHSH blobs but whoever had it didn't keep them up to date so I only have 4.1 and 4.3.1 blobs available on the servers. If for some reason my 4.2.1 JB went totally wrong and I had to downgrade to 4.1, what is the best method to use, the phone is I believe a Apple direct warranty replacement so is factory unlocked as standard,but I don't know which bootrom it has,I'm a bit reluctant to put it into DFU mode if I'm not JB'ing it, as I don't know how to get it out again, some say you can't some say you can, any advice would be most appreciated

[drog92]

well if it is factory unlocked then you shouldnt have any problems..... just go download tinyumbrella and tell it to retrieve the SHSH's that it has.... then start TSS server once you have an .ipsw for an SHSH that you have then open iTunes and do the normal stuff

[z3r01]

or wait for the new 4.3.1 jailbreak that might come today.

[drog92]

or wait for the new 4.3.1 jailbreak that might come today.

this is true.... it would be a lot less painful...

[brk1]

Thanks for the answers ,I'm not so worried about the restore bit,I can't go back to 4.2.1 as that blob was never saved,the youtube vids I watched showed them using Greenpoison to JB a device on 4.1 but it didn't tell you what version they used to do it, trying to find older versions of GreenP is no fun at all,then when you do get an older version,it doesn't say it can do a 3GS on 4.1. I have all my SHSH files stored on my PC .I have already had to do a downgrade on my sons 4G touch,it froze when connected to my laptop,something took one or the other down,the touch totally froze and would not boot up at all, and my laptop would boot up then totally freeze up as well,still don't know what happened there at all, so had to do recovery mode,restore to get it working again, the same day Apple changed to 4.3 from 4.2.1.,his blobs for 4.2.1 had been saved as soon as it was JB. My worries on 4.1 were regarding the old/new bootrom jailbreak, Greenpoison RC6.1 does both old and new without a worry,I didn't know if earlier versions would work the same way or not.

According to Spirit JB, 4.3.1 full untethered JB is available at 5 a.m tomorrow morning for the UK, keeping my eye on that, not too many about with 4.3.1 JBreaks yet to know how good it is,I'll grab the program and hold up for a while to see what happens,I've got three different SHSH blobs saved for 4.3.1, both kids 4G touches and my Iphone 3GS

[HappyTroller]

GP 4 is for 4.1 i believe

[drog92]

i do believe that the latest GP can be used on any of the versions.... you just have to try

[brk1]

I wasn't brave enough to just try, Greenpoison RC6.1 clearly states in its readme file, that the device must be on 4.2.1, most of the other older versions of GP don't come with a readme anymore. that was why I was hoping somebody on here had actually done a 3GS on 4.1,In my constant search , one post somewhere actually said RC2 was right but I couldn't find that version, it's even been removed from the GP old versions cache site.
Would have been nice to know for sure though.I'll try and grab some of the older versions to try.

4.3.1 is out now so I'll wait and see what reports come through before I make up my mind whether to upgrade or not, I already got the blobs for it on all our devices so no hurry.