Lowering the modem (rollback / downgrade) from 06.15.00 to 05.13.04 for iPhone 3G / 3GS
Finally, the opportunity to downgrade the modem. A working GPS is waiting for you. To check, you can use standard maps, if the blue dot blinks in circles, then GPS is working. If the point is static, then AGPS works.
Important! You can go down from any bootrom and only ONLY FROM MODEM 06.15.00 !
Only who has an iPhone 3GS 2011 23 weeks or newer - Starting about 23 weeks from 2011, apple began installing new flash chips on iphone 3gs phones. This led to the fact that it became impossible to unlock the phone through the modem firmware method from ipad, the phone "died". But, as it turned out, such a chip was not installed on all iPhones ... Who has an iPhone 3GS - 2011 is 23 weeks or newer, you will have to check in your workshop what chip you have (open the phone).
If the chip number is 36MY1EE , Spansion S72NS128RD0HL or Spansion 72NS128RDOAHBLO, you can update the modem safely.
If the chip number is 36MY1EH , do not update the modem , this will kill the phone’s modem flash drive!
Custom firmware for 3GS
For activation to work, you need to restart your iPhone two times.
We install custom firmware at your own peril and risk!
Custom firmware with a modem update on 06.15.00 (from iPad)
Custom firmware without updating the modem .
1. Run the redsn0w.exe utility (On Windows, be sure, with administrator rights!) .
Next, click on Extras , then on Select IPSW and point to the file in advance of the downloaded firmware that is currently installed on your phone. If you have an iPhone with a new bootrom, then you skip this point.
Click OK on the request.
Next, you will see a question about your version of the bootrom. Click Yes , if the new bootrom or No , if the old.
To find out which BR of your iPhone, on the main page of the rednsn0w program (In new versions), below is information about the connected phone.
In the rednsn0w program on your computer, return to the first menu with the Back button .
2. Next, follow the menu items of the utility, first turn off your iPhone completely by swiping your finger across the red slider. This is important because affects further firmware!
3. Click on the jailbreak button.
Preparation will begin.
4. Set the checkboxes on the Downgrade from iPad baseband and uncheck the Cydia , if it is already installed with you.
5. Next, click Next, and follow the activity of the lines for entering the iPhone in DFU.
- 1st line 3sec hold the Power button
- 2nd line, do not release the Power button and hold Home
- 3rd line, release the Power button, and hold the Home button until the display turns white on the phone.
Again, the preparation process ...
Your phone will reboot ...
The window that everything is ready, but the phone is not disconnected from the computer! ...
After you see the standard Pwnapple logo, Flashing Basenand appears on the screen.
IMPORTANT! This operation will take a long time, about 3-8 minutes. After everything is over, your iPhone 3G or 3GS will reboot, but with the modem 05.13.04 , which can be unlocked using ultrasn0w from Cydia. HOORAY!
Problems and Solutions
1. If the modem is down, but the network does not catch, reinstall Mobile Substrate in the side and reboot the phone.
2. If the modem after all the actions remains on 06.15.00, we reflash the modem on 06.15.00, we repeat everything again. I advise you to try on different firmware. And on a clean phone!