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-   -   Write protection on SPI flash? (http://www.usbjtag.com/vbforum/showthread.php?t=9501)

Teddy Boom 09-23-2017 03:39 PM

Write protection on SPI flash?
 
Working on some VDSL modems. Whenever I write the full dump from one particular model to an SPI flash, the chip can no longer be erased/written. I am holding both HOLD# and WP# high.

Doesn't matter if the chip is in system or loose on my desk. Tested with the stock flash from the device, of course. I've also written the dump to an MX25L128, but once written, that chip can't be written to again either.
(technically, written, soldered into PCB and run once, then desoldered--that might matter I guess :confused:)

I did a tiny bit of reading about the status register on SPI flash, but I'm not seeing the key bit of info..

Am I doing something wrong? Maybe I can edit the hex file to remove this apparent write protection?

usbbdm 09-23-2017 06:13 PM

Quote:

Originally Posted by Teddy Boom (Post 60869)
Working on some VDSL modems. Whenever I write the full dump from one particular model to an SPI flash, the chip can no longer be erased/written. I am holding both HOLD# and WP# high.

Doesn't matter if the chip is in system or loose on my desk. Tested with the stock flash from the device, of course. I've also written the dump to an MX25L128, but once written, that chip can't be written to again either.
(technically, written, soldered into PCB and run once, then desoldered--that might matter I guess :confused:)

I did a tiny bit of reading about the status register on SPI flash, but I'm not seeing the key bit of info..

Am I doing something wrong? Maybe I can edit the hex file to remove this apparent write protection?

I am not aware of a lock feature. If the flash can be read, then it should be able to write with proper setup. Unless for special chip, unlock command is available and needs to be used.

Teddy Boom 09-24-2017 03:57 PM

Quote:

Originally Posted by usbbdm (Post 60870)
I am not aware of a lock feature. If the flash can be read, then it should be able to write with proper setup. Unless for special chip, unlock command is available and needs to be used.

Thanks, I'll give it another try.


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