Q: I understand for production I usually need to fill things into Flash file system like UBIFS or jffs2, but now, I just want a quick stand alone boot up to show my customer my demo, how should I do this?
A: You may flash the u-boot into Parallel Flash, and store the uImage into SD card. Here I will give an example based on BF609 EZ-BOARD and 2012R2 release.
The basic idea is, Flash the u-boot into Parallel Flash, customize the u-boot environment variable, to make the u-boot read the uImage into a RAM location from SD card, and then jump to the RAM location to boot the uImage.
Step 1: Flash the u-boot.
i) download the tarball from https://blackfin.uclinux.org/gf/download/frsrelease/568/10222/u-boot-bf609-ezkit-2012R2-RC3.tar.bz2, extract it, file u-boot-bf609-ezkit-para-2012R2-RC3.ldr is what we want.
ii) Flash the downloaded u-boot-bf609-ezkit-para-2012R2-RC3.ldr into parallel following https://docs.blackfin.uclinux.org/doku.php?id=toolchain:ldr-utils
iii) after the Flashing is done, reset the board, you should see the u-boot UART console with minicom or windows hyperterminal etc with 57600-8-N-1 (make sure the boot mode of the board is set to Parallel Flash boot, position 1)
Step 2: Store the uImage into SD card
i) download the uImage from https://blackfin.uclinux.org/gf/download/frsrelease/593/10293/uImage-bf609-ezkit-2012R2-RC5 and rename it to uImage for simplicity.
ii)format a SD card into FAT (you may do this with a windows PC)
iii)copy the above file uImage into the SD card FAT partition (still on a windows)
Step 3: Customize the u-boot environment
In the u-boot console, run the following command
i) set mmcboot 'fatload mmc 0:1 0x1000000 /uimage; bootm'
ii)set bootm 'run mmcboot'
Step4: Reset the board
Reset the board, in a few seconds you should see it's booting into Linux.