From Utilite Wiki
The Trim-Slice firmware consists of two components: binary configuration table (BCT) and U-Boot. During Trim-Slice power-up the Tegra2 processor executes the internal BootROM firmware. The BootROM initializes the Tegra2 DDR memory controller and loads the bootloader. The DDR settings and bootloader location are specified in the BCT that should be present on the firmware boot media. U-Boot initializes the hardware modules necessary for system boot and loads the operating system.
To be added later.
The Trim-Slice utilizes U-Boot as the system boot-loader responsible for initializing the system and loading the O/S. U-Boot is a feature-rich, open-source boot-loader supporting flexible selection of operating system boot modes, scripting facilities and command line interface through serial port.
Firmware boot sources
The Trim-Slice supports the following firmware boot media options:
- Boot from SPI flash - used as the default boot mode.
- Boot from the front SD socket - intended mainly for system firmware recovery and bootloader development.
Normally, the Trim-Slice will always boot from the internal SPI flash. SD firmware boot may be forced by holding the recovery-boot button (located behind the micro-SD security door) during system reset or power cycle.