A method and apparatus are provided for facilitating access from a control system to the memory of a processor across two buses, one of which acts as a bottleneck to communication between the control system and the processor. A bridge between the two buses acts as an intermediary. The control system issues simple diagnosis and data loading verification commands across a slow bus to the bridge. The bridge then performs the data intensive tasks by communicating with the processor through a faster bus. The bridge writes and reads data to the processor, and generates checksums of the written and read data. The bridge then returns status information to the control system indicative of the comparison of the checksums. In the case of memory diagnosis, the control system need only issue a simple command to the bridge through the slower, which then diagnoses the memory through the fast bus by writing and reading data, and returns a status to the control system through the slow bus. In the case of verification of loading of data, the bridge generates a checksum of the written data and then generates of a checksum of the data it reads back from the processor through the fast bus, and returns a status to the control system through the slow bus.