Downgrade your Bose QuietComfort 35 II from any version to 4.3.6, 4.1.3, 3.1.8, 3.1.7, 2.5.1, 2.2.1, 2.2.0, 2.1.3 or 2.0.1 : r/bose
Did Bose QuietComfort 35 firmware upgrade make headphones sound worse? - CNET
Bose QuietComfort 35 II Noise Cancelling Bluetooth Headphones— Wireless, Over Ear Headphones with Built in Microphone and Alexa Voice Control, Silver : Amazon.in: Electronics
The Bose QuietComfort 35 Firmware Conspiracy Hole | by Alex Rowe | Medium
Bose QC35: update did not interrupt noise cancellation - Somag News