Apple recently seeded iOS 4.3.5 and good news for jailbreakers is that iOS 4.3.5 can still be jailbroken using redsn0w 0.9.8b4 (which was used to tether jailbreak iOS 4.3.4). This will work for all devices except the iPad 2.
The jailbreak is tethered though, meaning that you’ll have to connect your iPhone/iPod Touch/iPad 1 to PC/MAC and boot tethered after it reboots.
How To Jailbreak iOS 4.3.5 using redsn0w 0.9.8b4:
1. Update to iOS 4.3.5 using iTunes
2. Download & run redsn0w
3. Point to iOS 4.3.4 IPSW file (If you don’t have it, download it for your iDevice)
4. redsn0w will identify the firmware. Click Next to patch iOS 4.3.4
5. “Install Cydia” will already be selected on the next screen, click Next
5. redsn0w will now ask you to switch off your device and put it in DFU mode. Follow the instructions on the screen
6. Once this is done, redsn0w will port tethered jailbreak on your iPhone/iPod Touch/iPad 1 & you’ll have Cydia already installed
If you face any difficulties or have any queries, feel free to ask below!