Copyright
©
2019
congatec
AG
SX8X_SDS_q11
7/8
The following environment variables are predefined for conga-SMX8-X
(Prototype Revision Y.1):
Name
Default value
Description
bootcmd
Defines the startup command of the bootloader, i.e.
how the system performs the boot process
fdt_file
imx8qxp-cgtsx8x.dtb
The device tree blob, might be exchanged in order to
enhance functionality
image
Image
The name of the kernel image file that is loaded
during boot process
ipaddr
not specified
Address of the system (used for network boot)
serverip
not specified
Address of the remote host (used for network boot)
netmask
not specified
Netmask of the network (used for network boot)
nfsroot
not specified
The location where the NFS root filesystem is stored
(used for network boot)
mmcdev
"1" (external SD card)
The boot device number (used for mmcboot)
mmcpart
"1" (first partition)
The number of the bootpartiton on the bootdevice
(used for mmcboot)
mmcroot
"/dev/mmcblk1p2 rootwait
rw" (2nd partition on device 1)
The root filesystem (used for mmcboot), might also
be used to extend the kernel command line
Following, some frequently used scripts:
Name
Description
mmcboot
Boots the system from mmc (with the specified parameters for mmcboot), i.e.
eMMC, SD card
mmcargs
Configures the bootargs for mmcboot
netboot
Boots the system from network (with the specified parameters for network boot)
netargs
Configures the bootargs for network boot
loadbootscript
Used during boot, loads an eventually existing boot script
loadimage
Used during boot, loads the kernel
loadfdt
Used during boot, loads the device tree blob file
There are several commands to change the behavior of the bootloader and
to customize the boot process. The help command can be used to display
a list of all available commands.
2.4
Updating or Fixing the Boot Container
The boot container of the conga-SMX8-X (Prototype Revision Y.1) is stored
in SPI flash. To update or fix a corrupted boot container, boot from a
recovery SD card instead of SPI flash. Follow the steps below to create a
recovery SD card and update or fix the boot container:
1. Flash your root filesystem image to an SD card
1
("recovery SD card"):
dd if=your_rootfs.sdcard of=/dev/sdX
2. Write your boot container (SD) to the recovery SD card:
dd if=your_bootcontainer_sd.bin of=/dev/sdX bs=1k seek=32
3. Copy your boot container (SPI flash) to the recovery SD card:
mkdir
-p
/mnt/sd
mount
/dev/sdX1
/mnt/sd
cp -avr your_bootcontainer_fspi.bin /mnt/sd/.
sync; umount /mnt/sd
4. Insert the recovery SD card into the SD card slot of the carrier board
5. Set the DIP switches to boot from SD card (see step 2 of section 1.4)
6. Start the system (see step 12 of section 1.4)
7. Log in as root and enter the following commands:
cd
/run/media/mmcblk1p1
flash_eraseall /dev/mtd0
dd if=xyz_bootcontainer_fspi.bin of=/dev/mtd0
poweroff
8. Switch the PSU off
The boot container is updated. The recovery SD card can be removed and
the DIP switches set back to boot from SPI flash (see step 2 of section 1.4).
Note
1 Do not use the SD card included in the sample distribution set for this purpose.
