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I'm trying to flash the ROM externally now, but it's telling me it can't disable block protection. It gets as far as trying to erase 0x600000, then goes through all the erase functions, finally crapping out. Do you know how I can work-around that?
The write protect screw is removed, right? After that the flash's write protect register needs to be updated. Do you know the status register values? Flashrom should be able to do that.
Yes, it is definitely removed - I didn't put it back in after the initial brick. It says the register value is 0x94 - I did also hook up the Bus Pirate for use with statically linked ChromeOS Flashrom (as the particular version I have doesn't have Dediprog support) - I had an idea running --wp-disable might help, but it didn't recognise the chip and said the register was already 0x94 (paraphrasing). I am currently compiling a newer statically linked version of ChromeOS Flashrom using the SDK, in the hope that might be able to do the job. Am I barking up the wrong tree though, or is there something else I could do?
You are in the right spot. The fact that it failed at 6MiB is very indicative of the SPI part write protection. There are, however, more than one status register. There should be 3 of them:
Read Status Register-1 (05h), Status Register-2 (35h) & Status Register-3 (15h)
Btw, I'm referencing W25Q64FW datasheet.
-Aaron
Yeah, using --wp-status with Clapper's Flashrom tells me that the write protect *is* enabled, after all. But I can't see where, apart from the screw I took out right next to the battery, the write-protect screw would be? And I'm confused as to why it let me write initially if the write-protect wasn't enabled.
This is the output I get trying to run --wp-disable:
w25_set_srp0: old status: 0x94 w25_set_srp0: new status: 0x94 w25q_disable_writeprotect(): error=1. No -i argument is specified, set ignore_fmap. FAILED Setting SPI voltage to 0.000 V restore_power_management: Re-enabling power management.
I've sorted it out now - had to bridge pins 3,7 and 8 using a large paper-clip, as alluded to in the OSCON presentation, referenced by Barry Schultz. Never had to do that before, oddly.