Situation: A dual boot application using the LatticeECP2 device has both a golden bitstream that will not be changed, and a primary bitstream that is periodically updated in SPI Flash. In the dual boot configuration, the golden bitstream is never downloaded to the LatticeECP2 unless the primary bitstream fails to load properly. There are instances where a user might want to download the golden bitstream rather than the primary, regardless of the primary bitstream loading properly or not.
Answer: The LatticeECP2 dual boot with golden and primary bitstreams occurs when using the SPIm mode. By changing to SPI mode with the CFG pins all set low, the golden bitstream is always loaded from SPI Flash and the primary bitstream is ignored.
LatticeECP2/M Dual Boot Usage Guide.