Should a single SO-DIMM module work in DIMM2 slot in an HP laptop?

[Perplexer]

So I bought a second hand HP Zbook 15u G2 Mobile Workstation laptop with 8 GB memory in DIMM1 slot, which works OK.

I am now thinking of adding another 8 GB module to the other (DIMM2) slot but before I buy it, I tried moving the current 8 GB SO-DIMM module from the "DIMM1" slot to "DIMM2" slot to make sure that the second slot is OK. But when I turn on the laptop with the single module in slot "DIMM2" (and "DIMM1" unpopulated), the laptop doesn't boot. Caps lock and num lock lights are flashing, the fan spins at full power and the screen remains blank.

Is it possible that this is just "by design" and that a single memory module MUST be installed in DIMM1 slot ? I cannot find any confirmation on this in any HP manual.

It's probably just a limitation and not a defective DIMM2 slot, but I'm not sure and wanted to ask first. Thanks for clarification.

[Paul_Tikkanen]

Hi:

I cannot find any information regarding the the memory slot population in the service manual or elsewhere.

I have seen other posts regarding different model notebooks where that can occur if you install the memory in DIMM 2 rather than DIMM 1. 

They may be labeled that way on purpose, because many notebooks do not have the slots labeled leading me to believe that you can install the memory in either slot.

For example...if you look at the service manual for the older ZBook, they define a primary memory module and a secondary memory module.

c03985204 (hp.com)

But unless someone has your exact model notebook and has done what you did and reports the notebook produces the same error, then I doubt you will find the answer to your question until you actually install a second memory chip in that slot.