Firmware update application

You can use the mca_fw_updater command line application to update the firmware that runs on the Micro Controller Assist (MCA) of the ConnectCore 6UL.

The flash memory of the MCA is divided into two regions: program flash and NVRAM. Before writing the new firmware, this application completely erases the contents of the program flash through the MCA bootloader. By default, the NVRAM is also erased.

The MCA firmware is a critical part of the system. If you are not sure of the origin of your new firmware image or the benefits of updating it, do not proceed.
The bootloader must restart the MCA to re-run the application stored in flash, and this involves restarting the complete system.

Check the latest MCA firmware version available

Your ConnectCore 6UL system-on-module ships from factory with a pre-programmed firmware on the MCA. Digi, however, ships fixes and updates of the MCA firmware on the support web site.

Digi recommends you verify the current firmware version of the MCA and check for a more recent version on the Digi support site.

Go to the ConnectCore 6UL software product page on the Digi web site to check for the latest available MCA firmware version.

Check the current MCA firmware version

Verify the current MCA firmware on your SOM by reading it on the U-Boot banner:

U-Boot dub-2020.04-r2.2 (Jan 18 2021 - 15:58:10 +0000)

CPU:   i.MX6UL rev1.2 528 MHz (running at 396 MHz)
CPU:   Industrial temperature grade (-40C to 105C) at 32C
Reset cause: POR
I2C:   ready
DRAM:  256 MiB
MCA:   HW_VER=1  FW_VER=1.19
PMIC:  PFUZE3000 DEV_ID=0x30 REV_ID=0x11
NAND:  256 MiB
MMC:   FSL_SDHC: 0
In:    serial
Out:   serial
Err:   serial
Model: Digi International ConnectCore 6UL SBC.
ConnectCore 6UL SOM variant 0x06: Industrial Ultralite 528MHz, 256MB NAND, 256MB DDR3, -40/+85C, Wireless, Bluetooth
  Board version 3, ID 135
Boot device:  NAND
Net:   FEC0 [PRIME]
Fastboot: Normal
Normal Boot
Hit any key to stop autoboot:  0
=>

On a running system, you can check the MCA firmware version by running the sysinfo command.

Compatibility with MCA firmware

  • ConnectCore 6UL SBC Express: all MCA firmware versions are supported.

  • ConnectCore 6UL SBC Pro: MCA firmware v0.12 or higher required. Previous versions are not supported and should be updated using a debugger. See Program MCA firmware.

Command line options

Command line option Action

mca_fw_updater -v, --version

Show the current version of the tool

mca_fw_updater -h, --help

Show the available options

mca_fw_updater -f FILE, --file

Erase the flash completely and update firmware with file FILE

mca_fw_updater -f FILE -k, --keep-nvram

Update firmware but keep current NVRAM contents

Option -f erases both program and NVRAM flash sectors before installing the new firmware. If this option is used together with -k, the NVRAM will not be erased. Option -k alone is not valid; it performs no action.

Update MCA firmware

The firmware must be contained in a binary file, with read permissions for the user. When the program is invoked with option -f, it starts the update process:

MCA update process
~# mca_fw_updater -f mca_cc6ul_vX.XX.bin
The update process may take 20 seconds or more
During this process the chip drivers become unresponsive and you may
see I2C communication error messages on the console.
These error messages are expected and don’t interfere with the
firmware update process.
DO NOT POWER OFF OR RESET the device.
DO NOT CTRL+C OR ABORT this operation.

The program sends a message to the MCA firmware with the byte sequence for calling the bootloader and then checks that the bootloader is running. Then it performs the selected operations (update firmware, erase NVRAM). The process may take longer than 20 seconds, and the console displays a spinning bar. During this time, the system must be kept powered to successfully complete the update. Once the new firmware is written, resetting the MCA takes five seconds. Note that during the MCA reset process, the program appears to perform no action. The i.MX6UL CPU then reboots together with the MCA.

Do not abort the firmware update process. If the process is interrupted during the write phase, the MCA could be left in an inconsistent state. If the process fails you can retry manually, but success is not guaranteed. In this case, you can only recover the MCA by flashing the firmware with a debugger probe.
Digi recommends you use the mca_fw_updater application to update MCA firmware. If for some reason you are unable to do so, you can also use a debugger. See Program MCA firmware.

Detect invalid firmware images

The tool has a limited capability of detecting if a firmware can cause irreversible damage to the MCA flash. Consequently, it will not install firmware that:

  • Does not fit in the program flash memory, or

  • Can overwrite critical flash settings and prevent further updates (for example: lock flash against erasing or change clock settings).

Detection of invalid images
~# mca_fw_updater -f bad_binary
INVALID FIRMWARE - it can damage the MCA.
Update aborted
~# du -h a_very_big_file
4.9M    a_very_big_file
~# ./mca_fw_updater -f a_very_big_file
The firmware image does not fit in flash.
Update aborted.

If an invalid image that still passes these filters is written to flash, the functionality of the system will be lost. If this happens, you must use a debugger to flash a valid MCA firmware image. The application cannot re-program an MCA that contains invalid firmware; bootloader mode is required to program new firmware, and invalid MCA firmware cannot set the MCA to bootloader mode.

To avoid problems that may arise from flashing an invalid firmware image:

  • Only write firmware provided by Digi International Inc., designed for the MCA and fully supported by other software components.

  • Check the file name before pressing Enter.

Troubleshooting

  • Following Linux convention, the application returns 0 for success and a negative error code otherwise. Upon error, you can check the return code with echo $?.

  • If the update process fails unexpectedly but the application does not complain about the binary file size or format, retry the process. If this still does not work, the MCA firmware can still be updated with a debugger probe.

If you are able to enter U-Boot, you can use the following commands to probe the devices connected to the I2C1 bus (bus index 0):

=> i2c dev 0
Setting bus to 0
=> i2c probe
Valid chip addresses: 08 7e

The MCA has the slave address 0x7e. This means the MCA is present and running the firmware. If the address 0x7D is shown instead, the MCA is running the bootloader. If none of them is present, the MCA is faulty. If the MCA is running either the firmware or the bootloader, you can boot to Linux and try to update again.