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Not all flash is updateableNot all flash is updateablePosted Oct 19, 2006 7:23 UTC (Thu) by man_ls (subscriber, #15091)In reply to: No one uses ROM anymore, get over it already by svkelley Parent article: FSF should separate GPLv3 changes (Linux.com) I would imagine that not all flash memory inside a device must be made user-serviceable. Even that it takes some effort to make it updateable from software. So, set the flash contents in the factory and just avoid upgrades on the field, and effectively you have a ROM, right?
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Not all flash is updateable Posted Nov 2, 2006 17:27 UTC (Thu) by wookey (subscriber, #5501) [Link] Not really. Both nor and nand flash are intrinsically read/write. You could wire up a flash chip with the write line tied down so it couldn't be used bu then there is a problem about how to get the code into the device in the first place. Myabe you could do it with JTAG, but normally you have use JTAG on the CPU which then used the write line to get data into the chip.
In theory you could put some content in the chip before soldering it down, but the whole production process is now set up assuming that you don't have to do this sort of thing any more (and we all save money because of it).
So the 'just put it in ROM' is not a trivial thing. It requires significant design and production changes, if it is possible at all.
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