Certain Cypress (and Broadcom) Wireless Combo chips, when a January 2021 firmware update is not present, allow inferences about memory content via a "Spectra" attack.
https://www.informatik.tu-darmstadt.de/seemoo/team_seemoo/jiska_classen/index.en.jsp
https://github.com/RPi-Distro/bluez-firmware/commit/8445a53ce2c51a77472b908a0c8f6f8e1fa5c37a