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Forum / iMX6 Rex, TinyRex, OpenRex / Force boot from SD card

Force boot from SD card

BCVegas , 01-30-2020, 04:43 PM

Greetings. Is there any way to force an unprogrammed board to boot from the SD card? I have a blank SPI Flash device and default fuses on the processor.

robertferanec , 02-01-2020, 02:21 AM

If you are using iMX6, and you would like to test booting from SD card, this may help: https://www.imx6rex.com/open-rex/sof...with-software/

Especially the text at the end of the page:

Testing uBoot (optional)
OpenRex always starts booting from SPI. If you would like to test the uBoot on SD card, go to uBoot and run following commands:

Code:

mw.l 0x020d8040 0x2840; mw.l 0x020d8044 0x10000000; reset

Comments:

BCVegas, 02-03-2020, 03:55 PM

Thanks, Robert. I have an additional question. Is there any other way to program the SPI Flash memory on an OpenRex board beside through the USB OTG port?

robertferanec , 02-05-2020, 01:56 AM

Is there any other way to program the SPI Flash memory on an OpenRex board beside through the USB OTG port?

- I do not remember exactly (it was long time ago), but I believe you can program SPI from uBoot.

Comments:

surfbytes, 02-06-2020, 11:54 AM

Hello, I have the same question, so just to clarify ..OpenRex boots from SPI flash so there must be some code in SPI flash (uboot) to boot, correct ?And, for fresh boards with blank SPI flash, code must be uploaded to SPI flash, correct ?If all true, is OTG USB the only way to upload code to SPI flash or is there another method ?If true, then my custom board MUST have OTG USB installed, correct ?Thanks, -Randy

robertferanec , 02-06-2020, 11:58 AM

You really would like to have OTG USB flashing option available on your board.

PS: You could flash SPI before it is fitted on the board. Also, you can for example boot uBoot from SD card (if that is possible) and flash SPI. It all depends how your board is designed.

Comments:

surfbytes, 02-06-2020, 12:06 PM

Thanks for your quick response.Unfortunately our first custom board doesn't have OTG USB, but we should still be able to boot uboot from SD card and bring the board up, is that correct ?

robertferanec , 02-11-2020, 12:29 AM

Unfortunately our first custom board doesn't have OTG USB, but we should still be able to boot uboot from SD card and bring the board up, is that correct ?

It depends what are your fuse / boot option settings and if / how you can change them.

BCVegas , 02-11-2020, 11:04 AM

What is the correct Uboot file for the OpenRex board? The software section has a .bin file and a .imx file.

The .bin file is titled OpenRex_u-boot_2GB.bin

The .imx file is titled u-boot-imx6s-openrex_22-MAR-2016.imx

robertferanec , 02-12-2020, 10:24 AM

It depends ... if I remember right, one is with offset and the other one not (if you open the files in hex editor, you should see there difference where they start). So it depends how you are writing the file into the CPU or FLASH.

This may help: https://www.imx6rex.com/open-rex/sof...ot_empty_board

BCVegas , 02-14-2020, 04:37 PM

Hi Robert. Thanks for your feedback. We have the SPI programmed with the Uboot, but we don't have the ability to program the fuses. Is there some way we can force the board to boot from SPI flash?

robertferanec , 02-17-2020, 08:38 AM

@BCVegas you can find a lot of information about "How to ..." on our iMX6 Rex website :