i.MX8MQ Boot Modes Internal vs. Serial

[mmovsisyan]

Hello,

When BOOT_MODE[1:0] are set to 0b10 i.e. Internal Boot and BT_FUSE_SEL = 0, then "boot configuration parameters may be set using the GPIO". In other words GPIO settings override eFUSE settings and boot media is selected based on that. 

According to the reference manual, Serial/USB Downloader will be initiated after reset if BOOT_MODE[1:0] is 0b01.

My question is the following:

With BOOT_MOE[1:0] set for Internal Boot i.e. 0b10, will Serial Downloader be initiated if Internal Boot Fails? The Boot Flow and the diagram suggests that if Image Index < Max Image Index condition is not met, only then will boot be attempted from USB. 

Is this observation correct? And if so, what exactly does this conditional statement mean? When would this condition not be met?

SD/MMC manufacture boot flow seems to confirm this. Please advise. 

[igorpadykov]

Hi Mikael

>The Boot Flow and the diagram suggests that if Image Index < Max Image Index

>condition is not met, only then will boot be attempted from USB. 

>Is this observation correct?

yes

>And if so, what exactly does this conditional statement mean? When would this condition not be met?

one can look at sect.6.1.5.1.2 NAND flash boot flow, (Search Count)

  i.MX 8M Dual/8M QuadLite/8M Quad Applications Processors Reference Manual

>SD/MMC manufacture boot flow seems to confirm this.

right. Details can be found in footnote to Figure 6-2. Serial Downloader boot flow,

sect.6.1.10 SD/MMC manufacture mode

Best regards
igor