downgrade iPhone 4.1 to any unlockable version?

[psychosinks]

hello,
last week i got a iPhone 3Gs. that was fully functional. it's the first time i handled iphone. in that time I've done 'erase content and settings' under settings menu on iphone. then my phone didn't boot up. i guess i deleted phone's OS also. i connected iphone to my PC, sync with iTunes and restored and updated. i've updated to iOS 4.1. and then when i inserted my SIM, it shows Sim not supported. and showing 'iTunes-data cable' image on iphone.

some how I've inserted iPhone supported Foreign Country's SIM and got these menu. but not able to use phone anymore with bangladeshi SIM

Version: 4.1 (8B117)
Carrier: Carrier lab 8.0
Model: MC147C
Serial: 86930R2A3NP
Modem firmware: 05.14.02

i am frm Bangladesh
can i downgrade this iphone??
if there any step by step guide for me then help me
some body help me plz..

 

[pixelated]

I am afraid you cannot.
Even if SHSH blobs (signature hashes used for downgrading the OS) have been saved for that device, downgrading to a previous version will not change your Modem Firmware which would be needed to unlock your phone.
The only advice is to wait for an unlock to be developed for 4.1.

 

[Applejuiced]

Yes, like said above. No unlock available now.
Just jb.