The Raspberry Pi Pico 2, based on the RP2350 microcontroller, has become a useful hardware platform for research and testing on certain Apple devices based on the A12 and A13 Bionic processors.

In particular, the Pico 2 can be used with compatible BootROM research tools to place supported devices into Pwned DFU mode. This is an important stage for authorized low-level iPhone research, diagnostics, ramdisk development, data-recovery research and device testing.

Supported iPhone Models

The setup discussed in this article is mainly relevant to Apple devices using the A12 and A13 Bionic platforms.

A12 Bionic Devices

• iPhone XR
• iPhone XS
• iPhone XS Max
• iPad 8th Generation 

A13 Bionic Devices

• iPhone 11
• iPhone 11 Pro
• iPhone 11 Pro Max
• iPhone SE (2nd Generation / 2020)
• iPad 9th Generation 

These devices are different from older iPhone generations where software-based methods may be available for entering Pwned DFU mode. A12 and A13 devices require a different hardware-assisted approach for this type of research.

Why Raspberry Pi Pico 2 Is Used

The Raspberry Pi Pico 2 uses the RP2350 microcontroller. Compatible USB BootROM research firmware can use the RP2350's programmable I/O capabilities to communicate with the Apple device during the BootROM/DFU process.

In a typical research workflow, the iPhone is first placed into DFU mode. The RP2350-based hardware is then used to perform the required low-level operation, after which the device can be detected as being in Pwned DFU mode.

Pico 2 Setup for A12 Devices

For the A12 Bionic models listed above, the standard compatible Raspberry Pi Pico 2 configuration can be used without the additional 1KΩ modification described for A13 devices in this article.

Therefore, iPhone XR, iPhone XS and iPhone XS Max generally use the unmodified Pico 2 hardware configuration when the appropriate compatible firmware and research environment are being used.

Pico 2 Setup for A13 Devices

A13 Bionic devices require additional attention when using the Pico 2 configuration shown in this article.

The affected models include:

• iPhone 11
• iPhone 11 Pro
• iPhone 11 Pro Max
• iPhone SE 2020
• iPad 9th Generation 

With an unmodified Pico 2, an A13 device may fail to enumerate correctly after the hardware operation. In Windows Device Manager, the iPhone may not appear as expected, and the computer can report an error such as "USB Device Not Recognized."

1KΩ Resistor Modification for A13

For the A13 configuration described here, a 1KΩ (1000 Ohm) resistor is added as a jumper modification at the points shown in the image below.

What the 1KΩ Modification Is Intended to Solve

The purpose of the modification is to address the USB communication/ enumeration problem encountered with the A13 configuration.

Without the appropriate hardware configuration, the computer may fail to detect the device after the operation. After applying the correct modification, the A13 device can be used with the compatible research workflow and subsequently detected for further authorized testing.

Pico 2 Hardware and USB Wiring

When a standard Raspberry Pi Pico 2 is used with a modified Lightning connection, the USB signals must be connected correctly. A commonly used configuration is:

Warning: USB cable wire colors are not universal. Do not rely only on wire color. Verify the USB connections with a multimeter or a known pinout before soldering.

Never connect USB 5V/VBUS directly to the Pico 2's 3V3 pin. Also check carefully for shorts between VBUS and GND before connecting an iPhone.

From DFU Mode to Pwned DFU

The general research workflow is:

1. Prepare the compatible RP2350/Pico 2 hardware.
2. Install the appropriate firmware for the exact RP2350 board.
3. Prepare the supported iPhone in DFU mode.
4. Connect the iPhone to the RP2350 hardware.
5. Run the compatible BootROM research procedure.
6. Verify that the device has entered Pwned DFU mode.
7. Continue with an authorized ramdisk, diagnostics or research workflow.

Why Pwned DFU Is Important for Ramdisk Research

Pwned DFU provides a low-level environment that can be used by compatible tools to continue the boot process and load research or diagnostic components such as an appropriate ramdisk.

This is particularly useful for security research, forensic work, diagnostics and authorized data-recovery workflows on devices that you own or are authorized to service.

A12 vs A13 Pico 2 Configuration

Troubleshooting

iPhone Is Not Detected

• Check the Lightning cable and USB connections.
• Verify that the iPhone is actually in DFU mode.
• Check D+ and D− connections carefully.
• Check VBUS and GND for accidental shorts.
• Confirm that the correct firmware has been installed on the Pico 2.
• For A13 devices, verify the required 1KΩ hardware modification.

USB Device Not Recognized

If an A13 device produces a USB enumeration error or does not appear correctly on the computer, inspect the hardware configuration first. Incorrect D+/D− wiring, unsuitable firmware, cable problems or an incorrect resistor modification can all cause communication problems.

Conclusion

The Raspberry Pi Pico 2 with the RP2350 provides a compact and inexpensive platform for low-level Apple device research involving supported A12 and A13 devices.

For A12 devices such as the iPhone XR, XS and XS Max, the standard Pico 2 configuration can be used. For the A13 family, including the iPhone 11 series and iPhone SE 2020, the 1KΩ resistor modification shown in this article can be required for the particular Pico 2 hardware setup described here.

Always perform these procedures only on devices you own or have explicit authorization to service, and verify all electrical connections before powering the hardware.