x86 ROM Boot Loader
The x86 ROM boot loader, which is commonly referred to as romboot, is a small-sized boot loader that resides in system flash memory, usually as 256 KB flash electrically erasable programmable read only memory (EEPROM). During power-up, romboot handles the platform initialization tasks that would normally be done by the platform basic input/output system (BIOS). Once the platform is initialized, romboot supports downloading a boot loader image over Ethernet or booting the boot loader image from a local Integrated Device Electronics (IDE) drive.
Because romboot is designed to reside in flash memory, where the BIOS normally resides, the boot loader replaces the BIOS. This means that there are no BIOS features available to the operating system (OS). This also means that romboot configures the platform. Configuring the platform includes the following tasks: setting up the memory controller, host bridge, and PCI enumeration.
The primary advantage of using romboot is that it is a fast boot loader solution. Romboot is an alternative to LoadCEPC.exe and is designed to not require BIOS or Microsoft® MS-DOS®–based services for the x86 platforms that it supports, thus providing a faster boot and download alternative. The boot loader currently supports the Lanner EM-350 and EM-351 Embedded SBCs and the Advantech PCM-5822 and PCM-5823 Biscuit PC systems, though it can be extended to support many other chipsets. For more information about the systems supported by boot loader, see Lanner EM-350 and EM-351 Embedded Single Board Computers and Advantech PCM-5822 and PCM-5823 Biscuit PC.
The boot loader supports downloading an image over an Ethernet connection, using the Dynamic Host Configuration Protocol (DHCP) to obtain an IP address or by static IP, as well as from a local IDE/ATA hard disk.
Note When booting from a hard disk, you should place the binary OS image file, NK.bin, in the root directory of the active partition.
For more information about the x86 ROM boot loader and its functionalities, see the following topics:
- x86 Source Organization
- x86 ROM Boot Loader Porting to Other x86 Platforms
- x86 ROM Boot Loader Building
- Known Issues with the x86 ROM Boot Loader
- Troubleshooting the x86 ROM Boot Loader
See Also
Last updated on Wednesday, April 13, 2005
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