The ConnectCore 8X uses an NXP i.MX8QXP system-on-chip (SOC). NXP released two revisions of the SOC silicon: revision B0 and revision C0.

On i.MX8QXP C0 revision, NXP fixed most of the errata that were reported on B0. For a full list of fixes, see NXP Application Note AN12770.

The Security Controller (SECO) firmware of the SOC is different for each revision. This is a fundamental fix in the security chain that has the following important consequence:

The bootloader for a i.MX8QXP B0 cannot boot on a C0, and vice versa.

Digi Embedded Yocto generates different U-Boot artifacts for the different ConnectCore 8X variants for both SOC silicon revisions (B0 and C0). For example, for the default variant of the ConnectCore 8X SBC Pro, Digi Embedded Yocto produces:

  • imx-boot-ccimx8x-sbc-pro-B0-2GB_32bit.bin

  • imx-boot-ccimx8x-sbc-pro-C0-2GB_32bit.bin

You must select the U-Boot that matches the SOC revision of your ConnectCore 8X SOM.

Identify the SOC revision of your SOM

Visual inspection

The label on the ConnectCore 8X SOM looks like this:

ConnectCore 8X SOM label

The red circle denotes Digi’s revision of the ConnectCore 8X SOM. The following table correlates the ConnectCore 8X SOM revision with the i.MX8QXP SOC revision:

SOM revision Description i.MX8QXP SOC revision

1P, 2P…​

Pre-production series

B0

A, B…​

Mass production series

C0

On the U-Boot console

U-Boot prints the i.MX8QXP SOC revision on the banner, at the CPU line:

U-Boot dub-2020.04-r2.2 (Jan 18 2021 - 15:54:04 +0000)

CPU:   NXP i.MX8QXP RevB A35 at 1200 MHz at 25C
DRAM:  2 GiB
MCA:   HW_VER=1  FW_VER=1.01
MMC:   FSL_SDHC: 0, FSL_SDHC: 1
In:    serial
Out:   serial
Err:   serial
Model: Digi International ConnectCore 8X SBC Pro Board.
ConnectCore 8X SOM variant 0x02: 2 GiB LPDDR4, Wi-Fi, Bluetooth, MCA, Crypto-auth
  Board version 3, ID 135
Boot:  MMC0

 BuildInfo:
  - SCFW 56682d58, SECO-FW 0e4b9cee, IMX-MKIMAGE 8da5cd23, ATF c949a88
  - U-Boot dub-2020.04-r2.2

flash target is MMC:0
Net:   eth0: ethernet@5b040000 [PRIME], eth1: ethernet@5b050000
Fastboot: Normal
Normal Boot
Hit any key to stop autoboot:  0
=>

Bootable microSD artifact

Among the many artifacts that a Digi Embedded Yocto project produces, there is one with .sdcard extension. You can raw write this file to a microSD card and fully boot the ConnectCore 8X SBC Pro from it.

Digi Embedded Yocto only produces one .sdcard file that uses the default U-Boot artifact for the platform. The default U-Boot artifact is the one for the mass production series, that uses the rev C0 silicon. See Substitute the bootloader for information on how to change the bootloader on the sdcard image.

The default .sdcard artifact cannot boot on a pre-production ConnectCore 8X SOM (with a B0 system-on-chip).