Enabling SO-DOMM modules on the Talos II
The Talos II supports a large number of full sized DIMMs, however, in order to check the feasibility of a smaller form factor (read: laptop), the hardware and firmware need to be able to support SO-DIMMs.
The Sofra POWER9 CPU requires registered DDR4 RAM with EC. This is relatively easy to find in the full-sized form factor, however it becomes a bit harder to find in the SO-DIMM form factor. In this case, we actually need to use SORDIMMs (note the extra R for registered).
After contacting a number of vendors, I received a response from Viking Technology where they were willing to send 10x 16GB, 2666MHz SORDIMM to Digikey so that I could purchase a few sticks: https://www.digikey.com/products/en?keywords=VR9FR2G7228JBKSBD4 Datasheet: https://media.digikey.com/pdf/Data%20Sheets/Viking%20PDFs/PS9FRxx72x8xxx_Rev.E_3_7_2018_DS.pdf
In order to adapt the above modules to the full sized slot, something like the following can be used: https://www.amazon.com/gp/product/B07DMNH15W/ref=oh_aui_search_detailpage?ie=UTF8&psc=1
Before SORDIMM modules can be used, a couple of minor patches to the hostboot firmware must be made. The first patch is simply enabling hostboot to recognize that SORDIMM modules are valid.
Additionally, the Talos II firmware (as of 1.07) was unable to properly detect the manufacturer ID from the modules. As a quick test, I modified the hostboot firmware to treat a manufacturer id of 0 as Samsung. Once done, the RAM was detected and booted without issues.