BF70x hardware unique id

I am trying to read the Hardware Unique ID in the blackfin 707, but I am only reading 256 bits of zero back. 

The actual read command ( adi_rom_otp_get(otpcmd_huk, u32Buffer ) ) returns true.

Just to try, I changed the instruction cache to Disabled, and I have also tried to remove (CACHE_MEM_MODE) from {0x38000000, (ENUM_L1DM_DCPLB_DATA_4KB | CACHE_MEM_MODE | BITM_L1DM_DCPLB_DATA_DIRTY | CPLB_READONLY_ACCESS)}.

But I still read all zero.

Does this mean the unique hardware ID is 0? 

And on a side note.. is it really correct that instruction cache must be disabled? As mentioned I do not get any errors when accessing the otp. And why would the default configuration for OTP memory be CACHE_MEM_MODE, if this could result in read errors?