Downgrading iPhone 4 to older OS

[Daddy Mac]

I dont know if this is possible but can you downgrade your iPhone 4 OS to an older one. This may help determine if the proximity sensor issue is hardware or software right? I dont know how all this works so be kind.

 

[rattleglans]

I dont know if this is possible but can you downgrade your iPhone 4 OS to an older one. This may help determine if the proximity sensor issue is hardware or software right? I dont know how all this works so be kind.

I'm mostly sure you can't

 

[hipvamore]

yeah pretty sure not possible

 

[draz]

You can't because Apple releases specific firmware for each of their iPhones so there needs to be an iPhone 4 firmware for iOS 3.x.x which there is not.

 

[Applejuiced]

Like said above, not possible to downgrade it to anything but 4.0 cause thats the earliest firmware ever made for iphone 4's.
3.0+ firmware were only made for 2G, 3G and 3GS models.