Do I study DS or Embedded System for Facebook FRL system design interview?

I recently cleared phone interview for Meta's FRL SWE M1 role, and just had a prep session with the recruiter last week. The team I am targeted for develops SW tools for AR/VR HW (Embedded System), which is exactly what I am doing. During the prep, the recruiter says the system design round can be interview by a specialist regarding embedded system design including topic such as embedded coding, firmware, graphics and sensors. The other round can be done by a generalist for topics including distributed system. The design prep links includes bunch of CS topic prep like Grokking the System Design, Data structure etc, but non for embedded system. To me this doesn't sounds right. In all my previous roll like this, I just needed to know enough about embedded system in high level to be able to design and build the distributed system infrastructure and tools. I never needed to actually design an embedded system from scratch. Personally I don't feel it is common in the field for people that are well versed for both distributed system and embedded system at the same time. Let along being able to pass M1/E6 level technical interview. Given ~1 month of prep time, I feel that I can at most clear one or the other topic. Anyone who done interview for similar role that can share their experience? Did you end up having to study for both types of system design? Any resource for studying embedded system design? TC 530k YOE 13 #facebookbenefits #meta #systemdesign #interview #faang #swe