i.MX8MQ Access protection error while trying to set HDMI_DISABLE fuse

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i.MX8MQ Access protection error while trying to set HDMI_DISABLE fuse

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andrejakostic
Contributor II

I'm trying to disable HDMI on i.MX8MQ6DVAJZAA using the U-Boot 2019.04 fuse command.

In the reference manual, in the table Table 6-45 on page 1379, I've seen that at the address 0x450, there's bit number 25, which when set is supposed to disable HDMI.

 

Searching this forum, I found following formula for calculating the word an the bank on the i.MX8M:

uboot <bank> <word>

Bank = (address - 0x400) / 0x40 ; -> So in this case we have (0x450- 0x400) / 0x40 = 0x50 / 0x40 = 1

Word = [(address - 0x400) % 0x40] / 0x10 ; -> So in this case we have [(0x450- 0x400) % 0x40] / 0x10= [0x50 % 0x40] / 0x10 = 0x10 / 0x10 = 1

So far so good, after that I read the value of the fuses, and got 0x0802 2000, and after setting the it 25 to 1, I tried to write 0x0A02 2000, but I get the access protection error:

fuse prog -y 1 1 0x0A022000
Programming bank 1 word 0x00000001 to 0x0a022000...
mxc_ocotp fuse_prog(): Access protect error
ERROR

 

I'm not sure what I'm missing here, when trying to program those fuses? Is there a protect bit somewhere, which I missed?

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870 次查看
igorpadykov
NXP Employee
NXP Employee

Hi andrejakostic

 

>.. Is there a protect bit somewhere..

 

you are right, seems it is locked (protected from change) in factory.

 

Best regards
igor

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871 次查看
igorpadykov
NXP Employee
NXP Employee

Hi andrejakostic

 

>.. Is there a protect bit somewhere..

 

you are right, seems it is locked (protected from change) in factory.

 

Best regards
igor