On reset, the Oldland CPU begins fetching from the on-chip bootrom at 0x10000000. This bootrom uses CS0 on the SPI master to load a second stage bootloader from an SD card. The process is roughly:
- Initialize the SD card at a low clock speed.
- Read the first sector of the card, asserting that it is an MBR.
- Find the active boot partition.
- Mount the boot partition as a FAT filesystem and look for
/boot.elfand load it into memory.
- Execute the second stage bootloader.
This second stage bootloader would typically be something like u-boot and could then chain load an operating system such as RTEMS or Linux.