The UP Squared board (UP2) is an x86 maker board based on Intel platform Apollo Lake. The UP boards are used in IoT, industrial automation, digital signage areas etc.
SBL supports UP2 maker board. To start developing SBL, the following equipment, software and environments are required:
Before You Start¶
As you plan to reprogram the SPI flash, it’s a good idea to backup the preinstalled BIOS image first.
Boot the board and enter BIOS setup menu to get familar with the board features and settings.
UP2 is pre-installed with Ubuntu Linux. Boot to Ubuntu and confirm the display, USB, network and other peripherals are working.
Early boot serial debug console can be reached via UART0 located on CN16 header on the UP2 board. Make sure you can observe serial output message running the factory BIOS first.
To make your own UART debug adaptor by wiring, refer to CN16 Header Pinout for UART0:
In order to boot Ubuntu from eMMC using SBL, it is required to copy the kernel image to the boot partition (FAT32 partition) on the eMMC.
Alternatively, you can boot Yocto OS from USB key without any changes.
You may use utilities (e.g. Rufus) to create a bootable USB key from the Yocto OS image downloaded.
UP2 board is based on Intel Apollo Lake platform. To build:
python BuildLoader.py build apl
The output images are generated under
See Getting Started With QEMU on how to building SBL.
Stitch SBL images with factory BIOS image using the stitch tool:
python Platform/ApollolakeBoardPkg/Script/StitchLoader.py -i <BIOS_IMAGE> -s Outputs/apl/Stitch_Components.zip -o <SBL_IFWI_IMAGE> -p 0xAA00000E <BIOS_IMAGE> : Input file. Factory BIOS extracted from |UP2| board. <SBL_IFWI_IMAGE> : Output file. New IFWI image with SBL in BIOS region. -p <value> : 4-byte platform data for platform ID and debug UART port index.
See Stitch Tool on how to stitching the flashing IFWI image with SBL.
Booting Yocto Linux from USB¶
You may need to change boot options to boot from USB. See Change Boot Options.
- Download Apollo Lake platform Yocto Linux.
- Create bootable USB key
- Boot from USB key
Booting Pre-installed Ubuntu from eMMC¶
Booting Ubuntu from SBL requires a few extra steps because SBL default payload (OsLoader) loads kernel directly from boot partition, compared to UEFI BIOS which relies on GRUB 2 to boot Ubuntu.
- Boot to Yocto Linux from USB.
See Booting Yocto Linux from USB for more details.
- Copy vmlinuz and initrd file to
sudo cp /media/mmcblk0p2/boot/vmlinuz-4.10.0-9-upboard /media/mmcblk0p1/vmlinuz sudo cp /media/mmcblk0p2/boot/initrd.img-4.10.0-9-upboard /media/mmcblk0p1/initrd
config.cfgfile containing the following kernel command line and save it
BOOT_IMAGE=/boot/vmlinuz-4.10.0-9-upboard root=/dev/mmcblk0p2 earlycon=uart8250,mmio32,0x82531000,115200n8 <eof>