unable to prog fuse GP1, GP2

[jongho]

Hi

I am developing imx8mq SOMs from two third-party vendors.
Fuse GP1 and GP2 cannot be programmed in both vendors' SOMs.

u-boot=> fuse prog -y 14 0 ffffffff
Programming bank 14 word 0x00000000 to 0xffffffff...
mxc_ocotp fuse_prog(): Access protect error
ERROR
u-boot=>

If I type 'fuse read 0 0' in the u-boot,
then the result is 0xffffa9ab in the both SOMs
and that value means GP1_LOCK = 11, GP2_LOCK= 11.

If I read GP1 and GP2, the values are as follows.
This is also the same value for both SOMs.

u-boot=> fuse read 14 0 4
Reading bank 14:

Word 0x00000000: d503201f 55000801 0000a758 f2a01dc0
u-boot=>

Fuse GP1 and GP2 is not programmable in imx8mq?

[Harvey021]

Hi @jongho 

11 - OP + WP (The controlled field can be read or sensed only, but can't be burned or overridden in the corresponded OCOTP shadow register)

Best regards

Harvey

[jongho]

Hi

I think I understand OP and WP.

The following symptoms appear on SOMs purchased from two vendors.

(even though the GP-related fuse has not been touched after opening)

1. GP1_LOCK = 11, GP2_LOCK=11

2. the same initial value is written in both SOM.

I am curious as to why the GP is supplied locked.

The both vendors asked me to contact NXP directly about this issue.

[Harvey021]

General Purpose bank 1 and 2 have been repurposed for internal NXP use and should not be used by customers.

Best regards

Harvey

[jongho]

Hi

All right. However, I cannot find information related to this in RM and other documents.

Is there any document I can refer to?

Best Regards,

Jongho

[Harvey021]

I see the OCOTP_HW_OCOTP_LOCK from RM for GP1 and 2 for writing are reserved.

Best regards

Harvey