SMARC-sAMX8X User Guide. Rev. 1.1
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U-Boot standard environment variables are set up for the SMARC_sAMX8X module as shown below.
Table 12: Standard Environment Variables
Variable
Value
Description
baudrate
115200
Serial line baudrate
bootcmd
Run mmcboot || run sdboot || run usbboot ||
run netboot || run bootfailed
Try booting (in this order) from eMMC, SD
card, USB, network
bootdelay
3
Wait 3 seconds before executing bootcmd
ethprime
FEC0
Use Ethernet port FEC0 as default
loadaddr
0x80800000
Default memory location for OS boot
A typical user modification would be to set the variable "bootcmd" to change OS boot commands.
7.6.
Bootloader Environment Update
On the SMARC-sAMX8X it is possible to update the U-Boot environment separately.
This enables the user to either update from a previous version of the official Kontron sAMX8X U-Boot environment
(default U-Boot settings), or restore the default in case of problems.
Update procedure:
Download the official sAMX8X U-Boot environment from the Kontron EMD Customer Section.
For Release R10 of the sAMX8X U-Boot, the file is called ‘sMX8X-env-r10.bin’.
Put the file into the root directory of a FAT or EXT formatted USB drive.
Start the sAMX8X system and stop the boot process at the U-Boot prompt.
Run the following commands to load the file and flash it into the correct flash memory address (example
for R10):
usb start && load usb 0:1 $loadaddr sMX8X-env-r10.bin
sf probe && sf update $loadaddr 0x0c0000 $filesize
After reset the updated environment will be active.
7.7.
Kontron Bootloader Environment Extensions
To support SMARC_sAMX8X board properly, Kontron adds some environment variables to the standard set of
variables provided by mainline U-Boot. These variables are shown below.
Table 13: Bootloader Environment Extensions
Variable
Value
Description
boot_sel
Depends on
BOOT_SEL
lines
BOOT_SEL lines from carrier are evaluated during startup and
boot_sel is set appropriately. See chapter 0 Bootloader Boot Source
for more detail
core_variant
d
s
Set to "s" for i.MX8XS module, "d" for i.MX8XD module.
eth1addr
From EEPROM
Ethernet port FEC1 MAC address
ethaddr
From EEPROM
Ethernet port FEC0 MAC address
fdt_addr
0x83000000
Memory location for device tree blob
panel
Default: ld101
Describes the panel type attached to the module. It is used to select
