Abstract: A chipset (platform)-independent method and apparatus for compressing and decompressing a system ROM of a computer (e.g., BIOS, setup program, and one or more option ROMs) are disclosed. The setup program, option ROM, and part of the BIOS are compressed using a lossless compression algorithm. A non-compressible portion of the BIOS includes a decompression algorithm and a shadow RAM block table of chipset-specific registers and bit patterns to write-enable and read-enable shadow RAM (RAM that is mapped to the ROM address space). The compressed data is stored in a compressed data block format with the associated location in memory to decompress the compressed data. Thus, the data can be decompressed anywhere in memory of a target computer. For example, the BIOS is decompressed to shadow RAM and the setup program is decompressed to conventional memory. During the BIOS Power-On Self-Test (POST) process, the compressed system ROM is copied to conventional memory, and the decompression program is executed.