To write a boot loader program for the ADSP-21060, you'll first need to familiarize yourself with its architecture and booting process. Start by setting up the necessary environment, including an assembly or C compiler compatible with the ADSP-21060. Your boot loader should initialize the processor, configure the memory, and establish communication protocols (e.g., serial or parallel) to load the main application code from an external source into the DSP's memory. Finally, implement error handling and ensure that the boot loader can correctly jump to the application code once loading is complete.