The bootloader, one of the key software components included in the BSP, completes the required hardware initialization to download and run operating system images. The boot mode is selected from the S5 dipswitch on the carrier board and determines where the hardware looks for the primary bootloader. Set the S3, S4, and S5 dipswitches according to which interface you would like to boot from:
Locate the Boot Switch on the phyCORE-AM65x Carrier Board
SD Card
eMMC
Once the boot switch has been set appropriately, plug in a 12V supply to the X19 power port on the carrier board to boot.
Boot Options
The target can be booted from eMMC or SD Card. In our standard configuration, the kernel and root filesystem are loaded from SD/MMC.
The boot options for the kernel and root filesystem can be changed from within U-Boot. To enter U-Boot, after application of power, approximately three seconds are allotted for the user to hit any key which will halt autoboot of Linux:
help will show you the commands available to you in U-Boot and their usage.
Stand-Alone eMMC Boot
To configure U-Boot to boot the kernel from eMMC, modify the mmcdev and bootpart environment variables in U-Boot and save the environment:
Target (U-Boot)
setenv mmcdev 0
setenv bootpart 0:1
saveenv
CODE
Stand-Alone SD/MMC Card Boot
By default, the phyCORE-AM65x Development Kit is set up to boot the Linux kernel and root filesystem from SD. If switching from another boot configuration back to SD, modify the mmcdev and bootpart environment variables in U-Boot and save the environment:
Target (U-Boot)
setenv mmcdev 1
setenv bootpart 1:2
saveenv
CODE
Custom Boot
Unique boot configurations can be created by defining the desired environment variable settings and setting bootcmd to run its contents.
