I’m wondering how PEBB (Porsche Electrical Brake Boost - just made that up) is going to fail safe. With the ‘old-school’ vacuum boost you had enough ‘stored vacuum’ in the booster for 1 - 3 fully boosted stops if the engine was dead. I wonder if PEBB has a separate little battery for an emergency ‘dead-stick’ stop? Does it rely on the main battery for dead-stick operation? What happens when the alternator goes? Etc.

It may be like an aircraft in the sense that certain systems are permanently on the battery as a secondary power source (Hot battery bus, or switched hot battery bus). Electric brakes would be an obvious candidate, as would the head lights.

The 1990 Range Rover had electrically boosted brakes. That era Range Rover was my first experience with an electronically boosted brake system.

I assume things have moved on since then () but the system was hooked up to the battery so even with an alternator failure it still worked and had an accumulator to store pressure. Ignition would fail before the pump. It functioned as manual non-power brakes if the electronic power booster failed. I never saw or heard of one fail where you did not get a warning light first.

Honestly, other than the cost of replacement parts, I did not hate it. Pedal was very firm and had great initial bite, and once you got used to it, it was easy eoungh to modulate. It felt and worked about the same as hydroboost that would see on 3/4 ton and up pick up trucks. Compared to the similar era vacuum boosted ABS in the discovery, it was much superior in function.

I think it is all down to pedal feel, but unlike steering where hydraulic (or manual) inherently gives better feel because of variable feedback pressure, I see no reason why that would be true with brakes. NSX has a drive by wire brake system which I hope porsche’s is not. We shall see.