Alan Alexander wrote:
Many thanks for the information. Unfortunately I don't have access to the board schematics and getting technical support from the board supplier is proving rather difficult.
I have confirmed via an oscilloscope that both the WP# and TBL# pins are permanently pulled high - indicating that no hardware write protection is enabled (so it looks like I may have side stepped the GPIO locking issue).
The pins WP# and TBL# are active low and would be tied high even in the case of having write protection. Have you seen the WP# or TBL# go low on the scope during any of your write attempts?
I have also observed activity on the LFRAME#/FWH4 pin when
flashrom is attempting to write to the flash. Since I don't have access to X-ray equipment I think my best shot is to take a look at waveforms produced during a byte program cycle. I just need to get hold of that Logic Analyzer.......
That will tell you how much you have working during an attempt at a byte program cycle. Are you able now to write to the memory area below the top-boot-block of the Flash? If so, all you have left to do is find out how they control the TBL#.
-Bari