Uses for SPI Flash

[z4v4l]

it's not a durable to wearing out SLC NAND flash, it's NOR flash, it is NOT intended for what you are talking about, der geist der maschine. you already have brought a lot of confusion in this thread and keep on with this, even despite you know of the power of internet and doing research on it before stating something, then why you said it's unreliable to use, when it's not. creating uncertainty. the OP stated what he wants to do with it and it's acknowledged it's possible (given all the hassles of fighting with uboot are expected to deal with xD). putting there a FS and making it a general purpose volume is just stupid, because it's 16MBs, - you easily can use a USB stick gigabytes worth instead. with cryptographic keys again, this tiny storage won't make it any more secure - it's freely accessible. as of the real erase/program cycles this chip can endure, i don't know, i am typing this from a tablet, so can't check the specification, but i am almost sure, it's not this big as you claim. but it doesn't matter, because of so many other reasons. for example - what exactly wear leveling mechanism are you going to use? UBI/UBIFS? YAFFS2? the former dropped support for even MLC NANDs, i don't know if they even support NOR. anyway, you would need to recompile your kernel adding all the needed stuff there, configuring them properly. only for 16MB of a very slow storage (made for FW). .... good luck with that.

Edit. Yes, the specification states min 100000 E/P cycles durability. But this only fact doesn't justify hammering it imo. I just don't believe it will endure this much writings. if it is so stable, why SSDs break so often? look at this from this perspective - your normal x86 laptop has the same SPI NOR flash for BIOS/UEFI. would you be comfortable with rewritting it say once a week? I wouldn't. even knowing it's 100000 E/P cycles durable. It's a firmware storage device. period. btw, one of the reasons why uboot is mostly on  eMMC/SD on SBCs, is because it's easier to "play" with it for "tinkerers". For PBP on the other hand, which is a consumer device, it's much more important to have a consistent, reliable boot mechanism. users can easily mess up with their SD cards, forgetting what they put there and thus creating troubles for themselves, whereas having uboot on the permanently soldered SPI NOR chip and thus - always having a working "BIOS" inside, would be much better for them. just as with every laptop.