Need help downgrade from 4.2.1 to 4.0 or 4.0.1

[vietkool]

Upgraded to 4.2.1 and unlock with Redsn0w 2.1 , work great but only issue is the battery draining so fast (like 3%-4% for 1/2hr)with standby mode. I have google around and download Redsn0w 0.9.6b6 with SAM module do deactivate. Follow instruction like many many times but still couldn;t fix the battery issue.
So now, I'd like to downgrade to 4.0 or 4.0.1 what doesn't have battery problem like the 4.2.1 does. How do I do the downgrade? is it possible ? since I don't have SHSH blod saved before upgrading to 4.2.1 via itune.
please help

[ThaNatrix]

Download tinyumbrella and see if you can save shsh blobs for a lower version through there. If you can, use their tss server spoof and restore a custom firmware bundle for whatever version you want (it has to be custom). I don't know if that will work...worth a shot though.

[iLLz]

I remember reading something on redsn0w saying you couldnt downgrade .

[babyblue_pimp]

Have you tried to use the "deactivate" feature in cydia? Then you can activate with a ATT sim.

If you don't have ANY blobs saved, you wont be able to downgrade at all.

[westc0ast]

i had same issue try this 4.2.1, 6.15,SAM still drainin battery? FIXED
downgrading didnt help