Purpose of BOOT_CFG4[7], infinite loop?

[AlexHarford]

On the iMX6 there is a BOOT_CFG4[7] bit that says infinite loop enable. I would like to know what this bit is for, and if it would be useful for board bring up? Would it be useful to bring out to a test pad?

[raymondwang]

You should not set BOOT_CFG4[7] gpio bit(if you use gpio override setting) since it may cause MX6 enter infinite loops.

I encountered issue because of it on my rev1 board. You can see details @imx6q boot up failed with serial downloader mode or internal boot on new sabresd based custom board

[AnsonHuang · Accepted solution]

Hi, Alex

     If I remembered correctly, this bit is just for debug purpose, for example, if you found board can NOT boot up bootloader, you can enable this feature, and then connect JTAG into ROM code and debug it step by step to find why it boot fail. Not very sure about what you meant about "bring out to a test pad", can you explain more detail?

[AlexHarford]

I was trying to determine if this would be routed to our supervisor MCU as part of normal operation, or if it could be a test pad that we would use for board bring up only. It sounds like this is for board bring up only as it would never be used in a deployed situation. Thanks!