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i.mx6ull GP3 & GP4 burning issue

Question asked by courk on May 4, 2017
Latest reply on Apr 26, 2018 by Yuri Muhin

Hi,

 

We are trying to burn the GP3 and GP4 (General purpose fuse register 3 and 4, ranging from 0x880 to 0x8f0) by using the available sysfs entries. We are using NXP official BSP release 4.1.15_2.0.0_ga.

 

We are doing something like this:

echo 0xdeadbeef > /sys/fsl_otp/HW_OCOTP_GP30
echo 0xdeadbeef > /sys/fsl_otp/HW_OCOTP_GP31
echo 0xdeadbeef > /sys/fsl_otp/HW_OCOTP_GP32
echo 0xdeadbeef > /sys/fsl_otp/HW_OCOTP_GP33

 

Unfortunately, this doesn't work. Fuses are not burnt, the behavior is the same when we are trying to burn a locked fuse.

 

Nevertheless, based on the lock fusemap available on page 212 of the imx6ull reference manual, I can confirm GP3 and GP4 are not locked.

 

# cat /sys/fsl_otp/HW_OCOTP_LOCK
0x333f03

 

// 0x333f03 & (1 << 15) = 0

//  0x333f03 & (1 << 23) = 0

 

How can this behavior be explained ? I can confirm other fuses like HW_OCOTP_SW_GPn, HW_OCOTP_MACn, HW_OCOTP_GP1 or HW_OCOTP_GP2 seem to work as expected.

 

Thanks !

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