Suppose you want to configure a memory controller for supporting DDR4 memory chips without an SPD EEPROM (you are not using DIMM-like modules).
The common approach is to configure your board memory controller translating DDR4 datasheet information into the memory controller registers values and apply them.
Another approach could be using SPD-data (just a piece of software) in order to use SPD-to-memory-controller routines already available for other existing SPD modules.
Basically, micron-controller vendors provide SPD support for you.
For example, a number of these routines are available within U-BOOT code.
In other words you can think the SPD format like a standard format for memory controller configuration.
You can take advantage from existing SPD-to-controller routines generally provided by micro-controllers vendors.
It's simple to patch U-BOOT in order to use you fake-SPD-EEPROM !
So, if want to create an SPD image, this tool can be useful to you. It's free.