How to disable serial boot mode with fuse blowing?

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How to disable serial boot mode with fuse blowing?

Contributor I

Hello Folks,

I am working on imx6 dual lite board, I have programmed SRKH keys successfully by blowing fuses from kernel in /sys/fsl_otp.
Now, once board comes out of the factory or during production I wanted to disable serial boot using fuse register.

Hence, no one can connect OTG and flash uboot thorigh serial mode.

I know that BOOT_CFG4 is the right register to disable serial boot mode, but I don't know what value need to burn.

Also, I want to lock all the fuse register hence no one can rewrite again.

Could anyone please help me here.

Thanks in advance.

Shital Gandhi

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1 Reply

NXP Employee
NXP Employee


You can disable it with the SDP_DISABLE register. This register is in the fuse address 0x460. The register is set by default to 0, if you want to disable the serial download mode, you need to blow the fuse with a 1. However, this configuration cannot be reprogramed, is one-time programming, making it is by your own risk. Hope this information can help you.

Best regards,


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