The ConnectCore 8M Nano is shipped without a default operating system loaded. Only U-Boot is flashed in the device. This step demonstrates how to install Yocto in your ConnectCore 8M Nano.

1. Establish a serial connection with your device

Before you start programming the firmware, you must open a serial connection with the device. You can use any serial terminal program such as Tera Term, Minicom, CoolTerm, or HyperTerminal.

Due to an incompatibility between the USB/serial driver and the PuTTY terminal program, you must use another serial terminal program such as Tera Term, Minicom, CoolTerm, or HyperTerminal.

Open a serial connection with the following settings:

Parameter Value

Port

Serial port where the device is connected

Baud rate

115200

Data bits

8

Parity

None

Stop bits

1

Flow control

None

2. Program the firmware

Once you have established the serial connection, you can start the firmware update process. Follow these steps to install Yocto in the device:

  1. Download the firmware images from the following location:

  2. Decompress the zip file.

  3. Place the decompressed files in the root of a FAT-formatted microSD card and insert it in the microSD socket of the board.

  4. Reset the device by pressing the reset button on the board and immediately press any key in the serial terminal to stop the auto-boot process. The U-Boot bootloader prompt displays:

    U-Boot SPL dub-2020.04-r2.2 (Jan 18 2021 - 15:54:36 +0000)
DDRINFO: start DRAM init
DDRINFO: DRAM rate 3000MTS
DDRINFO:ddrphy calibration done
DDRINFO: ddrmix config done
Normal Boot
Trying to boot from BOOTROM
image offset 0x0, pagesize 0x200, ivt offset 0x0


U-Boot dub-2020.04-r2.2 (Jan 18 2021 - 15:54:36 +0000)

CPU:   i.MX8MNano Quad rev1.0 1400 MHz (running at 1200 MHz)
CPU:   Industrial temperature grade (-40C to 105C) at 36C
Reset cause: POR
DRAM:  1 GiB
MCA:   HW_VER=1  FW_VER=1.01
MMC:   FSL_SDHC: 1, FSL_SDHC: 0
In:    serial
Out:   serial
Err:   serial
Model: Digi ConnectCore 8M Nano Development Kit
ConnectCore 8M Nano SOM variant 0x01: 1 GiB LPDDR4, Wi-Fi, Bluetooth, MCA, Crypto-auth
  Board version 3, ID undefined
Boot:  MMC2

 BuildInfo:
  - ATF 9447098
  - U-Boot dub-2020.04-r2.2

flash target is MMC:0
Net:   eth0: ethernet@30be0000
Fastboot: Normal
Normal Boot
Hit any key to stop autoboot:  0
{pu}
    Information in the console log may vary.

  5. Install the firmware into the internal eMMC, executing the following command:

    => run install_linux_fw_sd

  6. Once the firmware is installed, the device boots automatically. The default username is root with no password.

During installation, error messages appear when the installation process attempts to override MAC addresses. These messages are expected.

## Resetting to default environment
oldval: 00:40:9D:7D:17:9A  defval: 00:04:f3:ff:ff:fa
## Error: Can't overwrite "ethaddr"
himport_r: can't insert "ethaddr=00:04:f3:ff:ff:fa" into hash table
oldval: 00:40:9D:7D:17:9B  defval: 00:04:f3:ff:ff:fb
## Error: Can't overwrite "eth1addr"
himport_r: can't insert "eth1addr=00:04:f3:ff:ff:fb" into hash table
oldval: 00:40:9D:7D:17:9C  defval: 00:04:f3:ff:ff:fc
## Error: Can't overwrite "wlanaddr"
himport_r: can't insert "wlanaddr=00:04:f3:ff:ff:fc" into hash table
oldval: 00:40:9D:7D:17:9D  defval: 00:04:f3:ff:ff:fd
## Error: Can't overwrite "btaddr"
himport_r: can't insert "btaddr=00:04:f3:ff:ff:fd" into hash table