Write protection on SPI flash?

JTAG software bug report.
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Teddy Boom
Junior Member
Posts: 14
Joined: Tue Jun 05, 2012 7:39 pm

Write protection on SPI flash?

Post by Teddy Boom »

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
Junior Member
Posts: 8979
Joined: Mon Jul 18, 2005 9:33 pm

Post by usbbdm »

Teddy Boom wrote: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
Junior Member
Posts: 14
Joined: Tue Jun 05, 2012 7:39 pm

Post by Teddy Boom »

usbbdm wrote: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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