Hi,
I'm not having Vybrid 3xxR series board in handy but i read OTP fuse registers in the i.MX6 processor without issues. I have followed the below link for this procedure, https://boundarydevices.com/fuse-command/
If you are going to follow above link, you may need to enable the corresponding kernel driver(OTP) in your SDK, now the OTP registers are export into the userspace directory(/sys/fsl_otp), then r/w the user data into those registers(most probably 2 WORD registers in the processor).
-> Kernel driver configuration:-Kindly ensure the kernel configuration as follows:
Device Drivers -> Character devices -> [*] Freescale On-Chip OTP Memory Support.
Could you please follow the above procedure & keep update your progress with us.
Also, i came across the below link, i shared for your reference,
https://community.freescale.com/thread/311716
Thanks