I have this exact same board (P8Z77-V) with the exact same CPU (i7-3770), the exact same DIMM's (4x 8GB CMZ16GX3M2A1600C9), and the same coreboot version (4.17), and it's working fine for me for months now.
When I leave CONFIG_NATIVE_RAMINIT_IGNORE_XMP_MAX_DIMMS to its default of n, the memory is clocked at 1333MHz (as the XMP profile says you may only use one DIMM per channel), but when I set CONFIG_NATIVE_RAMINIT_IGNORE_XMP_MAX_DIMMS=y, it's clocked at 1600MHz.
In both cases the system works perfectly well with 32GB RAM. (I tested 1333MHz in the beginning, and later switched to 1600MHz.)
So I don't understand why it wouldn't work with another identical setup. The logs show that the system reboots shortly after "SPD probe channel0, slot1". It seems to fail halfway during the probe, likely resulting in "Stored timings CRC16 mismatch." during the next try.
I've never tested the vendor BIOS on my board, so I have no idea if it should work there or not.
So why does the board reset halfway during an SPD probe? Could this be a faulty memory controller or something we're overlooking?