Bose QC 35 ii firmware 4.5.2

Friendly Fanatic

Re: Firmware 4.5.2 QC35 ii

Thanks for the response, 


- I can understand that the issue might be hard to replicate, and that it takes a while to diagnose a problem and create a fix for it

- However what I don't understand is why you don't just allow the firmware downgrade software, which you already have anyway, to let us downgrade back to a 2017 or 2018 firmware. You can even put up big disclaimers such as "do this at your own risk, downgrading firmware voids warranty" etc. Only a tiny tiny fraction of Bose users, mostly the users of this forum, will even know that this is a possibility. If you allow people to downgrade, the complaints will stop, and then you can take however much time is needed to diagnose and fix the problem, without having unsatisfied users or potentially bad press about this issue. 

Audible Advocate

Re: Firmware 4.5.2 QC35 ii

Hi Jeff. 

As many other user has already reported we don't understand the policy to not allowd us to downgrade the firmware; could you explain us why this isn't possible? This could help us to stop posting all the same request.
The downgrade would make us happy until a fixed version of the firmware will be released. On the contray if this option would be guarantte this could be seen as a clousure from the company.

To help the engeneers what I can tell you is that if I connect my set to windows 10 trought blootouth all the time that the system open the comunication the N.C. decrease drammatically. I'm preatty sure about this as I'm used to play white noise, if I play it the sound of the keyboard is quite clear if I stop the streaming the N.C. seems to be much more efficent.
Another observation is that, without playing anything, all the noises that comes from the frequncies around the voice spectra now are more clear.
 Hope that this could help the engeneers

Thank you for your collaboration and coomprehension.

Wistful Whisperer

Re: Firmware 4.5.2 QC35 ii

I updated through the Android app this morning in the office.

ANC *seemed* to be working OK on High, Medium noise cancelling was exactly the *same* as High!

So I used the Updater App from my PC.

Same as above.

I did a soft reset - Bingo!

High and Medium now differentiated.

Low is definitely low nc - but more active eq, ie sounds a lot better to my ears, and useful in a situation where you might want some situational awareness.

High now doesn't have the ear suck effect, but seems to be fine otherwise.

Also, I noticed in the Bose App there's now a setting to turn off voice prompts, don't remember seeing this before?






Audible Advocate

Re: Firmware 4.5.2 QC35 ii

I have a similar situation, my Android app says 4.5.2, the web updater says 4.1.3, after using 2 different devices, the ANC becomes wonky, and then after a charge/reset it clears up - only to get wonky again after I connect it to two bt devices or plug it in via the wire.

At this point updating via the web updater might fix my problems, but I'm afraid to be stuck at the wonky ANC permanently :/
Friendly Fanatic

Re: Firmware 4.5.2 QC35 ii

Hi Jeff,
Thank you for getting back to us.
Guys is anyone thinking of returning their Bose QC35ii as this will quicken the process instead of us all moaning. I would return mine but I don’t live within America and don’t have other headphones to compensate this.
Audible Advocate

Re: Firmware 4.5.2 QC35 ii

I have called support to make a complain for this issue and my headphones were shipped in.. they are scheduled to arrive today... let me know if you need information to locate them

Friendly Fanatic

Re: Firmware 4.5.2 QC35 ii

Jeff G, I have been posting about this issue for over 10 months and as far as I can see you have not offered to replace my headphones with a working pair so that you can use mine as a test sample. As I have explained I can’t return mine for a refund, so would jump at the opportunity to get mine replaced so you have a sample headphone with the issue.

Please message me.
Friendly Fanatic

Re: Firmware 4.5.2 QC35 ii

Before they blocked the ability to downgrade the firmware I did this several times with different firmware versions, including very early versions that I couldn’t see people had said caused them the ANC issue, and downgrading made little to no difference. It’s only my assumption but it seems this is more of an issue with the update maybe not quite working 100% as expected as it certainly doesn’t seem to impact everyone, and therefore corrupting some data, does anyone know if these headphones have a basic ANC calibration done at the factory? If so it could be that the calibration data is being modified/corrupted and so downgrading firmware couldn’t correct this. Again it’s just my thoughts rather than what is likely happening, but I just wanted to confirm that myself and several others had tried to downgrade our firmware and it didn’t restore the ANC back to how it was.
Audible Advocate

Re: Firmware 4.5.2 QC35 ii

Silly question, has anyone tried to downgrade? Bose used to allow you to do that, all you need to do is use the updater on your computer instead of your phone and use the ADV up down key combo. Or is this now blocked?

I haven't tried myself, I've updated to the latest firmware on my QC 35ii's and I can't tell the difference ANC wise.

Strident Supporter

Re: Firmware 4.5.2 QC35 ii



Re: Firmware Downgrade QC35

Hi Issamelmansori, 


Thanks for your post and welcome to the community. 


We no longer offer a downgrade for software. Hosting a downgrade option has become less and less of an industry standard. This is due to the significant level of difficulty/complexity of compatibility testing multiple devices with a large number of older firmware versions. We have seen cases where installing older versions of firmware can create unexpected behavior in a product and negatively impact or reduce functionality.


If you are having issues with your ANC on your QC35's I would highly recommend performing a product reset on the system. This can be done via: 


  • Turn off the headset and wait 30 seconds
  • Plug the headset into a wall outlet using a USB charger, then wait 5 seconds
  • Unplug the USB cord from the headset and wait 1 minute
  • Turn on the headset


Kind Regards, 

Hector B - Community Support