Bose launched firmware update 4.5.2 for the Bose QuietComfort II headphones about a month ago. And ever since the update, users have been reporting progressively worse noise cancellation technology.
However, the problem doesn’t seem to be widespread. Not everyone is experiencing it, and it appears that those who do, their ANC settings are stuck on “Low”.
Bose offered a statement to The Verge, noting that firmware update actually had nothing to do with noise cancellation / ANC settings. That said, users are encouraged to not revert their firmware back to the previous version. Of course, while Bose says this, anyone familiar with software knows that a slight bug or error on a completely different set of features can cause things to go haywire elsewhere.
One user posted to the Bose Support Forums with his own “solution” that users are encouraged to try.
source: Android Authority