Beside putting in the cache, I've been looking at a simple way of bootstrapping Merlin without the monitor, but also in a way that doesn't need a big SD card routine. I had a PMOD ESP32 from an earlier project, so I've added a UART to my design and can now send "AT" commands to access the internet and also use the flash filesystem on the ESP32. 

The ESP32 is already setup to connect to my wifi and has a custom os with the filesystem enabled. As you can see WIFI is connected and there is already a test file on it.

I think next I'll write a program to transfer a BIOS binary to the flash and then also boot from it at start up.