SDHC Boot Image

Building a bootable SDHC card is simple. In your eCos project, look for:

CYG_HAL_STARTUP and change it from RAM to SD.

This will enable CGHWR_MEMORY_LAYOUT_SD so that the linker script adds all the description data required for boot. Essentially, the Boot ROM in the iMX6 will read this data from the SDHC card, will setup the memory manger and clocks, then load and run the application.

This is not supporting signing the application or any security features.

There is no support for FLASH boot.

To make the SDHC card, you can't just copy the file to the SDHC card. Instead, you do something like the following:

arm-eabi-objcopy --gap-fill 0x00 --remove-section .noncache --input-target elf32-little --output-target binary app_name app_name.bin

fdisk /dev/sdb (partition 1; start at cyl 256)

mkfs.vfat /dev/sdb1

dd if=appName.bin of=/dev/sdb seek=2 skip=2 bs=512 && sync

Then you plug the card into the SDHC slot and reset the target. This is pretty much the same way you make a Linux bootable SDHC for these boards, other than the method of compiling the image with the description data may be different.

Testing: 04/26/2014 SVN Rev 129 tested ok for Sabre. Current changes should not break Wandboard.