Multiple boot devices

[prithvi_gautham]

1 > During boot set to FlexSPI-QSPI0, if the flash device connected to SS0 does not respond, then does IMX try SS1?
2 > If answer is yes to above question, then can there be two flash devices - one connected to SS0 and another connected to SS1. So that if device on SS0 does not respond (assuming device on SS0 is damaged) then imx8x can boot from SS1 (assuming device on SS1 is working)
3 > IF answer to 1> is No, then what options are there to have two boot devices , one on NAND controller and one on FlexSPI? (I cannot use SD or eMMC for my application)

[Yuri]

Hello,

The following boot stages are supported:
• Primary Image Container Set Boot (Primary Boot);
• Secondary Image Container Set Boot (Secondary Boot), assuming the same boot device 

   as for the Primary Boot;
• Recovery Boot;
• Serial Download Boot.

Primary Boot Device:
• The boot device selected by the boot mode pin or fuse.  The valid options include

SD/MMC/NAND/FlexSPI. For FlexSPI SS0 is used. The SS1 is intended for 8-bit mode
with flash A2.

Recovery Boot Device:
• After failing to boot from the Primary Boot Device, the ROM will attempt to boot
from another boot device. For this chip, the ROM will attempt to boot from
USDHC1 port if the Primary/Secondary boot fails.

Serial Download Boot Device:
• This is the device (e.g. USB, UART) running the serial download protocol (SDP), so
that the host can load the image into memory and ask for authentication. For this
chip, the valid option is USB.

  Use Chapter 5 (System Boot) of i.MX 8DualX/8DualXPlus/8QuadXPlus  Reference Manual

(Rev. 0, 05/2020) for more details. In particular, look at Figure 5-2 (High Level Boot Flow (1 of 3) - SCU

ROM Boot Start, Figure 5-3 (High Level Boot Flow (2 of 3) - SCU ROM Boot Image Handling), and

Figure 5-4 (High Level Boot Flow (3 of 3) - SCU ROM Boot Error Handling)

https://www.nxp.com/webapp/Download?colCode=IMX8DQXPRM 

Regards,

Yuri.

[prithvi_gautham]

Thankyou Yuri for the repsonse. I read through the boot articles in the processor manual and i understand that if primary and secondary(offset) boot fail, then recovery boot is initiated on USDHC controller that can interface a SD or eMMC flash. 

Once the primary boot fails, is there an indication / output provided to the user ? 

Is there any work-around to configure two separate devices for primary/secondary boot?

Regards

Prithvi

[Yuri]

Hello,

   Boot log may be used to analyze boot process. App note AN12853 (i.MX ROMs Log Events)

describes it. But there is no external outputs here.

https://www.nxp.com/docs/en/application-note/AN12853.pdf 

 Boot process is fully controlled by boot ROM, and there are no other options,

that provided in the boot chapter of the RM. 

Regards,

Yuri.