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i.mx6ULL separate boot and kernel media?

Question asked by David Luberger on Jun 5, 2018
Latest reply on Jun 8, 2018 by David Luberger

I'm having a hard time sourcing in low volume a flash device that can hold both the boot loader (u-boot) and the yocto project linux build (i.e., the kernel). Together, these need about 900MB of storage so I need at least 8Gb (1GB) of flash memory. Most of that I'm sure is the kernel, so what I'm wondering is: can I have the bootloader run on something small but cheap and reliable like spi NOR flash and then have the kernel run on an external SD card? My issue is that I just don't want to rely on an external SD card for my product to work. With the bootloader and console port, I can do all my diagnostic stuff without even having linux running, and at least if they lose the SD card, I can still debug the device or (I think) even do SFTP (to download via wifi?) a new kernel.  Does this make sense?  I hate that eMMC isn't readily available. Sure, Mouser and Digikey carry a few, but the one benefit of using an SD card is I can stick essentially any SD card in there.  With something like spi NOR flash, I have ready availability from lots of manufacturers with a common pinout, and it's fairly fast and generally is only a couple bucks.  NAND flash just seems like a huge pain to connect and configure (so many pins!) and having read about things like error correction and bad block management, it's a wonder to me that anyone uses it outside of SD cards, as it just sounds super unreliable, plus it's expensive and not readily available.