Hi Biju, Andre,

sctlr_el3 = 0x0000000030c5183a

The MMU is still disabled since we're so early in BL31, so nothing preventing us from making an actual access to physical address 0x0.

As Andre already noted:

x30 = 0x0000000000000000 elr_el3 = 0x0000000000000000 far_el3 = 0x0000000000000000

It looks like we do have an errant null pointer dereference here.

If I had to guess, the I-side successfully fetches a 32-bit word from physical address 0x0, but then fails to decode that bit pattern as a valid opcode. This is reported as "unknown reason", like you're seeing:

<quote Arm ARM DDI 0487E.a pp D13-2963> This EC code is used for all exceptions that are not covered by any other EC value. This includes exceptions that are generated in the following situations: - ... - Instruction encodings that are unallocated. - ... </quote>

Hope that helps, Ash.