It has not been long since Apple seeded iOS 4.3 Beta for developers to try out, and for those of you who don’t have the UDID of your iOS device registered on an Apple developer account can now restore your iPhone, iPad or iPod touch on iOS 4.3, apparently through a method posted at RedmondPie.

The instructions are as follows:
Quick Guide on how to "hacktivate" iOS 4.3 without a developer account.
1. Method
1) Install iOS 4.3
2) "Jailbreak" with redsn0w 0.9.6rc8, you should see a white block in de upper left corner from your iPhone, reboot it
3) get iFunBox
4) navigate to "Raw File System" -> /System/Library/CoreServices
5) open SystemVersion.plist and remove the following lines:
<key>ReleaseType</key>
<string>Beta</string>
6) Reboot the iPhone
7) Activate your iPhone with iTunes
2. Method (thx to joshingknight)
1) Restore to 4.2.1
2) Shift-Update and point the 4.3 IPSW. here’s important that you Shift-Update, not Shift-Restore!
If you want File System Access just jailbreak it like you were on 4.2.1 and reboot your iDevice when it’s stuck on a black screen, then you have FS Access with tools like iFunBox, but Cydia won’t work
Congrats your iPhone is activated now =)
Greetings from Switzerland..
Disclaimer: We at Sizlopedia.com recommend that you get enrolled in the iPhone Developer Standard or Enterprise Program in order to get complete access to all current and future iOS Beta releases. The above mentioned methods are meant for informational purposes only.