Recover your device | ConnectCore 6UL

Perform a rescue boot

If the bootloader has been erased from the storage media (or written with an invalid image) and the target does not boot, you can:

Boot in USB debug mode

Boot in USB debug mode

Requirements

Linux host computer.
Root/administrator permissions on your host computer.

For the ConnectCore 6UL SBC Pro:

A USB serial cable for the console.
A micro USB cable for recovery.

Instructions

Download the U-Boot bootloader binary image file from https://ftp1.digi.com/support/digiembeddedyocto/5.0/r3/images/ccimx6ulsbc/x11/

See U-Boot files by variant to verify which U-Boot binary you need.
Download the latest Universal Update Utility (UUU), a software tool from NXP.

UUU version should be v1.5.11 or higher.
Place the uuu executable in a directory in your PATH, such as /usr/bin.

Install udev rules to allow any user to run uuu to access the USB port:

$ sudo sh -c "uuu -udev >> /etc/udev/rules.d/70-uuu.rules"
$ sudo udevadm control --reload

Connect a USB serial cable to your host computer and the other end to the target CONSOLE connector.
Connect a micro USB cable to your host computer and the other end to the target USB recovery connector (USB OTG on the ConnectCore 6UL SBC Pro).
Change the boot mode configuration to boot from USB. To do so, close the BOOT jumper near the CONSOLE connector.
Open a serial terminal at 115200/8/n/1.
Power up the board.

On the host computer, run the uuu tool with the U-Boot file to boot as parameter. For example:

$ uuu  </path/to/u-boot-file>

When TrustFence support is enabled, Digi Embedded Yocto builds a special signed U-Boot file u-boot-dtb-usb-signed-ccimx6ulsbc.imx. Use this file to recover a closed device from USB.

The serial terminal shows the device starting U-Boot.

When booting in USB recovery mode, U-Boot runs the command in variable bootcmd_mfg, which runs fastboot command by default, to await commands from the USB port. Press Ctrl+C to get the U-Boot prompt.

Once you have booted U-Boot, you can proceed to re-program U-Boot into the NAND. See Re-program U-Boot in the NAND.

Re-program U-Boot in the NAND

Once U-Boot is running, you can use it to update the bootloader in the NAND:

Reset the environment to default values:
```
=> env default -a
```
Reset to the default partition table into the NAND:
```
=> run partition_nand_linux
```
Save the environment with saveenv.
Use one of the following methods to update the files to the NAND:

Re-program bootloader from USB using Fastboot

To update U-Boot via USB device using uuu and the Fastboot protocol:

Connect a micro USB cable to your host computer and the other end to the target USB recovery connector (USB OTG on the ConnectCore 6UL SBC Pro).
Then, on the target, run the fastboot command from the U-Boot console, selecting the USB interface you want it to listen to:
```
=> fastboot 0
```

On the host, run uuu to update U-Boot into the NAND:

$ uuu FB: ucmd setenv fastboot_buffer \${loadaddr}
$ uuu FB: ucmd setenv forced_update 1
$ uuu FB: download -f <file>
$ uuu FB: ucmd update uboot ram \${fastboot_buffer} \${fastboot_bytes}

Change the boot source configuration to boot from the internal NAND. To do so, remove the BOOT MODE jumper.
Power-cycle the board. The target now boots from the NAND.

For additional commands and information, see the NXP UUU manual.

Re-program bootloader from Ethernet (TFTP)

Place the U-Boot binary inside your host computer TFTP exported folder.
On the target, configure your network settings (IP of the device, IP of the host/server):
```
=> setenv ipaddr <your-ip>
=> setenv serverip <server-ip>
```
Connect an Ethernet cable to the Ethernet port.
Run the following command to update U-Boot into the NAND:
```
=> update uboot tftp <u-boot-filename>.imx
```
Change the boot source configuration to boot from the internal NAND. To do so, remove the BOOT MODE jumper.
Power-cycle the board. The target now boots from the NAND.

Re-program bootloader from microSD card

Place the U-Boot binary inside a FAT-formatted microSD card.
Insert the microSD card in the board.
Run the following command to update U-Boot into the NAND:
```
=> update uboot mmc 0 fat <u-boot-filename>.imx
```
Change the boot source configuration to boot from the internal NAND. To do so, remove the BOOT MODE jumper.
Power-cycle the board. The target now boots from the NAND.