Big RAM and the kernel debugger data block

I recently was provided with a 64GB raw memory image created by the free DumpIt tool from a Windows 2012 R2 x64 server. To my dismay, neither Volatility nor Rekall could make heads or tails of it. After debugging a little further, I discovered that neither tool was able to find the kernel debugger data block (_KDDEBUGGER_DATA64) structure.