Got 17.17.4 on my EAP S90D yesterday, and tried summon from my garage this morning.
WOW! Summon is starting to show its awesomeness!! Why do I say that: two weeks ago on previous firmware (17.11.3) I tried to summon from my tight garage. She did open the door (homelink) and started to back out, but stopped halfway inside the garage. I pressed reverse again to continue but she started to turn off the concrete and into the garden. Opps..... FAIL!
Today with 17.17.4 I tried again. Wow, what an improvement! Homelink opened garage door, then she back out all the way onto my driveway (30' or so), steering carefully to stay in a straight line, and closed the garage door when safely outside.
PASS! Summon is starting to grow up into a usable feature!