HMI430/700: NVEM2 (Read/Write)
NVEM2 isn't non-volatile, it's actually 64kB of RAM. This blasts through the SPLat 250 byte RAM limit and is great for logging. The catch is you'll need to use NVEM instructions to read & write data into this space.
Keep in mind any data you store here will not be saved when power is switched off.