This section describes the recovery (flashing) mode of the AC100 and how to reach it. The recovery mode is part of the NVIDIA development process for the NVIDIA Tegra 2, the system-on-a-chip (SoC) mobile processor used in the AC100. The recovery mode enables you to flash different operating systems optimised for the Tegra 2 onto the AC100 and it must not be mistaken with the “return to factory defaults” function.

Only use the recovery mode if you know what you are doing!

How to reach the recovery mode:

Hold down the CTRL + ESC/back keys and power on the AC100.

To use the device in recovery mode install one of the OS support packs provided by NVIDIA. The different OS support packs can be found here.

Note that the linux4tegra support pack includes the fastboot.stock.bin bootloader which appears to be more feature complete than than the bootloader.bin found on the Android support packs.

Linux Works without any additional drivers. (tested with Ubuntu 10.04.1) To be able to use the AC100 in recovery mode without beeing root on the host system, you might want to create a udev rule under /etc/udev/rules.d/ granting youself the rights you need. The udev-rule could look something like this: SUBSYSTEM==“usb”, ATTR{idVendor}==“0955”, ATTR{idProduct}==“7820”, MODE=“0660”, GROUP=“plugdev” (This grants read and write access to root and all the users in the group plugdev)

Windows When the AC100 is in recovery mode Windows looks for a driver for an “APX” device. The APX device driver is part of the already mentioned OS support packs. Once the driver is installed, Windows will show the device as “NVIDIA USB Boot-recovery driver for Mobile devices”, and it is then possible to run the nvflash utility.

Note: If the AC100 is connected to mains power while in recovery mode, you can return to recovery mode after powering down by holding just ESC/Back and powering on (CTRL not required). Once you lose mains power you will need to use CTRL + ESC/back again, as described before.