Modem downgrade (rollback / downgrade) from 06.15.00 to 05.13.04 for iPhone 3G / 3GS
Finally, the possibility of a modem downgrade. A working GPS is waiting for you. For verification, you can use standard maps, if the blue dot blinks in circles, then the GPS is working. If the point is static, then AGPS works.
Important! You can go down from any bootrom, and only ONLY WITH MODEM 06.15.00 !
Only who has the iPhone 3GS 2011 phone, 23 weeks and newer - Starting around 23 weeks since 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's firmware from the ipad, the phone was "dying." But, as it turned out, such a chip was not installed on all the iphones ... Whoever has the iPhone 3GS phone - 2011 is 23 weeks and newer, you will have to check in the workshop what chip you have (open the phone).
If the chip number is 36MY1EE , Spansion S72NS128RD0HL or Spansion 72NS128RDOAHBLO, you can safely update the modem.
If the chip number 36MY1EH , do not update the modem , it will kill the modem flash drive phone!
Custom firmware for 3GS
In order for the activation to work, you need to restart your iPhone twice.
Custom firmware install at your own risk!
Custom firmware with modem update for 06.15.00 (from iPad)
Custom firmware without updating the modem .
1. Run the utility redsn0w.exe (On Windows, of course , with administrator rights!) .
Then 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 are missing this item.
Click OK on the request.
Next you will see a question about your version of bootrom. Click Yes , if the new bootrom or No , if the old.
To find out what is the BR of your iPhone, on the main page of the program rednsn0w (In the new versions), below there will be 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 utility menu items, first completely turn off your iPhone, swiping your finger across the red slider. This is important because affects further firmware!
3. Making money on jailbreak .
Preparation will begin.
4. Set the checkboxes on the Downgrade from iPad baseband and uncheck the Cydia checkbox if it is already installed.
5. Next, click on Next, and follow the activity of the lines for entering the iPhone in DFU.
- 1st line 3 sec hold power button
- 2nd line, do not release the Power button and hold Home
- 3rd line, release the Power button, and the Home button hold 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 finished, your iPhone 3G or 3GS will reboot, but with modem 05.13.04 , which can be unlocked using ultrasn0w from Cydia. HOORAY!
Problems and Solutions
1. If the modem is lowered, but the network does not catch, reinstall Mobile Substrate in Sidium and restart the phone.
2. If the modem after all actions remained 06.15.00, we reflash the modem at 06.15.00, we repeat everything from the beginning. I advise you to try on different firmware. And on a clean phone!