I notice there is a 16mb spi flash on the bottom of my orange pi zero.

 

I read it is possible to boot off it.  Has anyone done it, and is it useful?  Is it possible to run without the sd card?

 

I am interested in locking the sdcard to read only for reliability during power loss, and storing application configuration data to the spi flash if possible.  Can it be mounted with a filesystem, or is it better to use a ramdisk and store it periodically to flash?

 

If you are talking about having Armbian full image stored in that SPI_NOR, no, it is too small ... But, an OpenWRT image would fit .

If you are talking about just placing a U-Boot loader there and booting from USB, yes, it have been done before.

Unfortunately, it seems that current u-Boot is currently broken for USB boot right now.

But it is possible to use older Apritzel u-boot, I've one built back in May and still working to boot from an USB HDD.

 

what about mounting the flash as a filesystem?

10 hours ago, seandepagnier said:

what about mounting the flash as a filesystem?

I would not recommend doing that, it has relatively low write speed and may have less erase cycles than usual NAND or SD/eMMC. In theory you could mount something like ubifs (and partitioning the flash before) but I would also not recommend doing it on the 3.4.x kernel.