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Question about manufacture boot flow and criteria

Question asked by ko-hey on Jan 22, 2018
Latest reply on Jan 23, 2018 by Yuri Muhin

Hi all


I have some questions about USB download mode via USB_OTG.


My customer's setting is as below.


Internal Boot mode (BOOT_MODE[1:0] = 0b10)
GPIO_BOOT_CFG1 = 0b01010010
GPIO_BOOT_CFG2 = 0b00001000
GPIO_BOOT_CFG4 = 0b00000000



Also flow is as below.

By GPIO setting, specify booting from SD connected to uSDHC2.
Do not connect anything to the uSDHC 2 interface, intentionally causing the boot to fail.



I tested with i.MX6ULL-EVK with the red line boot sequence of Attachment which is a Figure 8-27 of RM.

I confirmed that it worked booting from MFG mode with BOOT_MODE == 2.
I think that it will fall into USB download mode if MFG mode fails.

Am I correct ?



If BOOT_MODE == 0, booting from both MFG mode and USB download mode has been confirmed. (Blue line)

Does BOOT_MODE mean that the judgment criteria of "success?" In MFG mode will be different?
Because if you cut off the power of eMMC connected to uSDHC 1 trying it, you can enter USB download mode even with BOOT_MODE == 2 confirmed.
With BOOT_MODE == 0 there is no need to cut off the power of the eMMC, and if there is no boot image, even if power is supplied to the eMMC, it is judged as "failure" and enters the USB download mode.



Could you tell me the criteria of it ?