A20 board with NAND - how to boot linux from SD card

[Mar2333]

Hi,

I have problem with my OLinuXino A20 board. I would like to boot debian linux from SD card (original, from shop), but I don't how to set up bootloader, or disable NAND memory.

I found many tutorials how to make bootable SD card, but no one how to boot this card. Can you give me some advice?

Or is it possible to change boot order during start of the board? Like in BIOS at desktop computer, but I don't have a HDMI display connected to test it, just touch screen connected with 40-pin cable.

Thanks for any advice

[JohnS]

linux-sunxi wiki gives boot order imposed by CPU.  It tries to boot off uSD before NAND I think.

John

[martinayotte]

Yes, the boot order is uSD first, then, fallback to NAND.
If your uSD didn't boot, it is probably corrupted or defective.
In such case, take another uSD and put the latest images on it and try again ...

[JoseQ]

Is there a way to force to boot from NAND "if" the image on the SD card is corrupted?

I did some tests in the A20-Lime2: Debian in NAND, Debian in uSD card.

I intentionally corrupted the image on the SD card, and it gets blocked, UART outputs this:

<UART>

Code Select Expand

[i]  reading uEnv.txt
  ** unable to read file uEnv.txt
  Failed to mount ext2 filesystem
  ** Unrecognized filesystem type
  reading boot.scr
  ** unable to read file boot.scr
  Failed to mount ext2 filesystem
  reading uImage
  ** Booting kernel from Legacy Image at 480000000 ...
    Image Name: Linux-3.5.90
  ...
  ...
  ...
  verifying Checksum ... Bad Data CRC
ERROR: can't get kernel image!
sun7i#[/i]
 
</UART>

Thank you guys!

[JohnS]

I think it will boot from NAND instead but not if it thinks the SD card is OK.

So, some corruptions (try a blank card) will (probably) boot from NAND but others are where BROM has already thought the card was OK and by then you're in some bootloader not BROM.

Similar thread https://www.olimex.com/forum/index.php?topic=5097.0

John