on 15/05/2008 13:24 Stefan Reinauer said the following:
What's the mainboard? Maybe the mainboard protects the chip with an additional GPIO line.
Yes, this turned out to be the case. I glimpsed "somewhere" that on this motherboard value in IO register 0x4037 has to be and-ed with 0xef to enable writing to BIOS area (i.e. bit 4 has to be cleared). In my particular configuration 0x4000 is power-management IO base of PIIX4. And PIIX4 spec says that registers 0x34-37 control GPO signals (general purpose outputs). So this would make it, what, GPO28.
I did that and: $ ./flashrom -r -v -f bios.3.dd Calibrating delay loop... OK. No coreboot table found. Found chipset "Intel PIIX4/4E/4M", enabling flash write... OK. SST39SF020A found at physical address 0xfffc0000. Flash part is SST39SF020A (256 KB). === This flash part has status UNTESTED for operations: PROBE READ ERASE WRITE Please email a report to flashrom@coreboot.org if any of the above operations work correctly for you with this flash part. Please include the full output from the program, including chipset found. Thank you for your help! === Reading Flash...done Verifying flash... VERIFIED.