I had discounted Edge Gallery because it didn't support system prompts, but now it does so I will give it another go. I believe the implementation does use MTP since I got an update to Gemma-4-E4B on iOS indicating such, and on macOS it's very speedy.
However, on my 18GB RAM MacBook Pro, selecting Gemma-4-12B-it results in this error:
> The model "Gemma-4-12B-it' requires more memory (RAM) than is available on your device.
So yeah, my questions about the 16GB marketing copy are fair.
Interesting; they may have fluffed up somewhere then.
(Though perhaps it'll squeeze in with a small context window? Not sure I understand that aspect yet)
It does seem to use MTP, yes, and it is quite quick — seemingly the underlying LiteRT stuff can do MTP with Gemma 4 and presumably MTP is a big part of the practicality picture here.
The system prompt thing was a surprise when I poked around.