iOS 4.3.2 update to iOS 6

Is your phone currently jailbroken? If so, check the SHSH's you have available on cydia.
https://cydia.saurik.com/upgrading/shsh.html

(Is your phone an old bootrom 3GS? If so, it's untethered JB for life...)

 

Open cydia and click TSS center on the front page. At the very top, what SHSH blobs does it say cydia has for your device?

If there isn't any TSS center option, wait for cydia to finishing downloading packages and reloading

Btw, the iPhone 3GS can be tether jailbroken on 6.1.3

 

Unfortunately, you don't have that option. The only version you can restore to is iOS 6.1.3 and a tethered jailbreak. There are no other workaround methods since you don't have any SHSH except for 4.1

 

Just out of curiosity, why didn't you update to iOS 5? 4.3.2 to 6.1.3 is a huge jump, so why did you skip iOS 5? 4.3.2 means it's been 2 years since you updated.

 

You can't. You can only update to the latest 6.1.3 (6.1.4 if iPhone 5)

 

It doesn't work that way anymore. You can download by simply searching on Google.

 

If your phone was manufactured after the 27th week of 2011, you cannot downgrade it. There is a tutorial on iClarified.com to flash the iPad baseband, then downgrade the baseband. USe the older version of Redsn0w specified in the tutorial.

And "your friend" is incorrect, you cannot update to any iOS5 firmware without saved SHSH.

 

Just to add to what dhlizard said, 27th week of 2011 means manufactured after the 4th of July.