I mean, unless someone REALLY clever knows how to design a DDR DRAM replacement, but since there's no clock running to the memory, I assume that's impossible.
@twylo You could make a complex board with an onboard clock generator, but it probably isn't worth the effort.
Is there a reference for the timings seen on the 3B2? Do you have part numbers for the DRAMs it uses?
A DRAM-ish wrapper around an SRAM shouldn't be too difficult. The key is that you need latches, which are clocked by RAS and CAS: they are strobes, which are clocks by another name.
@EdS Thanks for these pointers! A colleague of mine has a board design using a 72 pin SIMM adapter. The major advantage there seems to be that 72 pin SIMMs are relatively cheap on the used market, and are basically a drop-in with no extra glue logic needed. A kludge, perhaps? But maybe the best idea.
"I appreciate SDF but it's a general-purpose server and the name doesn't make it obvious that it's about art." - Eugen Rochko