Hi Reinhard, On Mon, Jan 31, 2011 at 08:17:36AM +0100, Reinhard Meyer wrote: > Dear Albert ARIBAUD, Simon Guinot, > > > >>>>Here is the protect area map for a MX25L4005A 4Mb flash: > >>>> > >>>> bit 2 1 0 | protect level > >>>> ____________|_______________ > >>>> 0 0 0 | none > >>>> 0 0 1 | block 7 > >>>> 0 1 0 | block 6-7 > >>>> 0 1 1 | block 4-7 > >>>> 1 * * | all > >>Block size is 64KB. The compiled U-Boot image is about 220KB and > >>environment is 4KB. So, 4 blocks are required for U-Boot. > > I don't know your particular hardware, but is not u-boot (or the > initial bootloader if there is any) fetched from the *beginning* > of the flash? > > If so, you would have to *hardware* protect the *entire* flash.
Yes you are right. Moreover the protected blocks (for a same register value) _could_ be different on an another Macronix device. For example, larger flash use 4 bits instead of 3 for block protection. > > In this case, a *software* protection mechanism like for NOR flash > would be a better choice. Or no protection at all. After all, there is no such mechanism implemented for u-boot and Linux... Best regards, Simon
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