Well I can answer that! You can’t roll back (or at least it is very difficult to do unless you have the previous firmware file and know what you are doing). Apple don’t allow you to roll back more than one version and they only allow that for a few days.
I don’t know anything about Phonak firmware, but maybe there is a firmware update for your hearing aids? With Resound you can just download and install new firmware from the app, but with Phonak you might have to see your audiologist.
I have been dealing with this issue for months.
I had a iPhone SE2020 with the issue. I have an open issue with Apple tech support. Apple tech agrees there is an issue. All I hear from tech is data from my phone has been passed on through the Apple supports systems. No answers and I have to contact my tech to ask on status. I think he wants me to just go away.
Well I thought maybe the software update 14.2.1 that only iPhone 12’s got fixed the issue. I placed a post on this forum asking if users were experiencing issues on iPhone 12’s. No negatives and not much response. So I purchased a new iPhone 12 mini. Guess what I still have the same problem! The iPhone 12 mini has the exact same static issue as the iPhone SE2020.
By the way I have KS9 hearing aids.
I’m beginning to believe that the problem may be in the program setting on the hearing aids. I would think that if every Phonak marvel/KS9 user with an iPhone 12 had the issue there would be posts here and more information on internet searches.
I have the SE2020 with OPNS1 aids and I don’t have the issue with the static with Bluetooth streaming, but since the update to 14.3 I am seeing issues again with the aids stay connected, mostly when I also have connectivity with my TV adapter. The only thing I haven’t tried is to pair again with the TV adapter and I will do that this evening.
Agree. I’ve got the same issue with my work iPhone SE2020 and I’m using Phonak P90-R. I’ve just upgraded the phone to iOS 14.3. Will do some tests tomorrow. I don’t have the same issue with my iPhone 12 Pro which works flawlessly. Note problem on SE2020 only affects voice calls - never when streaming Spotify, YouTube etc.
It seems the SE 2020 has it with Bluetooth classic and not MFI
I am new here.
You can try: 1. setting- general-reset- reset network setting, then restart your phone; 2. open MYPHONAK APP, upper right corner-my hearing aids-my bluetooth phone calls, choose a different bandwidth (adaptive or fixed).
Hello - been lurking on here but I’ve signed up so I could post a reply. If anything to say “me too”
I’ve just got an iPhone 12 Pro Max with a pair of Phonak Marvels and experiencing the same thing. I’ve updated to iOS 14.3 hoping for the issue to be fixed as indicated with lots of other posts here but alas the problem still exists. I’ve tried the following:
Both worked temporarily for a few hours but alas the problem returned. Am seriously considering returning my iPhone as Ive never had this problem on Android.
Thanks for all the input everyone. It’s good to see that other people are having issues.
For me the static in one ear only happens when on a phone call randomly. If I stream from YouTube it’s fine. If I just use one hearing aid in the right ear everything is ok on the phone call.
Then once I put the left hearing aid back in the issue reappeared. I then restarted the phone and it was ok for a while.
My bet is that there is some build up of some interference from the iPhone going on which messes up the Bluetooth communications between both hearing aids. I heard that one hearing aid is sending Bluetooth data directly from the right ear hearing aid to the left ear hearing aid. This might explain why there is only static interference in the left only.
What is odd is that the iPhone 12 Pro was working fine when I first got it with the hearing aids. Since then the IOS has been updated a few times. I even sent Phonak a message explaining the issue. They replied back saying please see your audiologist.
The IOS 14.2.1 update sorted out the hearing aid Bluetooth issues with the iPhone 12 family specifically. IOS 14.3 doesn’t list Bluetooth as something that is changed, except for an availability of the option to control it in one screen.
I think those people who unfortunately have problems with crackling and connectivity with iPhone SE 2020 and iPhone 12, especially if with both, have probably got a Bluetooth fault in their HAs and it would probably be worth getting them serviced as a next step.
Thanks @Micah6-8 - I was on Adaptive, and will try Fixed and see how that goes, though I won’t hold my breath…
@david.hendon Thanks - I searched around the forum here and quite a few have reported issues with bluetooth HA’s from multiple different models and brands and iPhones experiencing the same issue and can have the same temporary solutions, for the same problem to return the next day or so. Also, this has worked absolutely fine on my Android phone previously.
I agree with a few other posts here saying it isn’t so much the bluetooth of the HA’s, but rather the Bluetooth stack hardware on the iPhones, which also may cause interference in communications between the left and right HA (hence why it would fix itself when the secondary HA is turned off). The frustrating part is that it’s intermittent - so it may work fine for a while (and will probably work perfectly when showing it to a technician, etc), but will kick in at some random point.
I really don’t want to go through the predicted rigmarole of trying to fix it with both sides of the HA/iPhone fence blaming the other and getting nowhere. For such an investment in a phone that so proudly claims “It just works” - it just doesn’t. Unless either side puts their hand up and says “Ah - we’ve found the specific problem to these HA’s, and here’s how to fix it”, the iPhone is going back.
It works, as long as you’re in the apple ecosystem. At least that’s what are my impressions.
I wonder how come that you went from android to iphone in the first place? People make that switch because of the aids not supporting direct android streaming OR go phonak which works on android (for older phones). I think you’re the first person I’ve seen to go phonak AND switch to iphone 
The reasons were unrelated to my HA’s (though in hindsight I should have looked much deeper into it). I was a long time Android user (10+ years) and specifically got the Marvels because it worked with Bluetooth Classic (ie Android compatible and other devices).
I made the (very tentative) step to iPhone because I wanted a better camera and for the better app ecosystem (was bored of feeling Android versions of some apps were an afterthought), and had assumed that my HA’s would “just work” just like my Note 8 did. Luckily I’m within my return window, so will hastily make my retreat back to my Android comfort zone…
Thank you for this thread. I have had this issue for many months and wondered if other people who wear Marvel hearing aids do as well. I purchased the Marvel hearing aids M90s a few years ago. I had an iPhone 6 and an iPhone 8 for work. Both had no issue with Marvel’s bluetooth streaming. During spring 2020, I upgraded from the iPhone 6 to iPhone SE 2020. I noticed the same crackling/static other people have described. It only occurs on phone calls, voicemail messages, and I think once possibly on FaceTime. It seems to only happen when the other person is talking, and I’ve heard the other caller can hear it as well, but only when I’m talking. The crackling is not consistently bad, as some calls are nearly perfect, others have mild static, and some are so static-filled that continuing on Bluetooth is nearly impossible.
I do find that sometimes restarting my phone and/or re-pairing the devices helps for a time, but it never resolves the issue. The MyPhonak app doesn’t seem to help. I’ve tried the adaptive vs. fixed bandwith. Apple’s Bluetooth settings, such as mono audio and the hearing aid button don’t help me either.
I have worked with Apple support for months, eventually being transferred to a senior adviser who is supposedly in close communication with their engineering team to resolve the issue. No Apple software update has resolved the issue for me. I borrowed some other iPhones in my family over the summer to test out the Bluetooth, and all of the following iPhones have the same issue: iPhone XR, iPhone 11 Pro, iPhone 11 Pro Max. I have not had a chance to try an iPhone 12 series phone yet.
I also had my audiologist download a Phonak firmware update in October 2020, but that did not help either. My audiologist is reaching out to Phonak for a resolution, but they claim its just the phone that is an issue. I’m not sure I agree, given that they release firmware updates after major iPhone releases.
The only workarounds I know of are to use my Phonak Roger pen as a headphone or to stream the call from my iPhone SE to the old iPhone 6, which I can do when the phones are near each other and signed into my Apple ID. When I stream to call to my old iPhone 6, I hear absolutely no static, but that only works if someone calls me, as the old iPhone 6 does not have cellular service anymore.
I also have Verizon on the personl phones but the work phone is AT&T. I wonder if there is some sort of signal issue, but I doubt it. I would be curious if other people who have had this issue have AT&T?
My guess at this point is that there is something about the newer iPhones and possibly the Marvel hearing aids as well that are not working well together with the Bluetooth. It would be nice if a combination of Apple software updates and Marvel Phonak updates could resolve the issue, but like some other people who have posted here, I am not convinced that will happen. Will keep trying.
I remember when every suggestion to bluetooth problems on this forum was “just get an iPhone.” 
I see that Resound have now included the four iPhone 12 models in their list of compatible phones for their hearing aids and apps.
Edit: And so has Phonak now too.
By the way the “Bluetooth stack” varies from model to model, especially in phone 12 as they use a different Bluetooth chip to earlier iphones.
Thanks for taking the time to write your post.
Everything you have mentioned is identical to my issues. The only difference is that I came from an iPhone 7 to the iPhone 12 Pro.
Since purchasing the iPhone 12 Pro on release day. My Phonak Marvel hearing aids seem to be working fine with Bluetooth and phone calls.
Then there has been further IOS releases since the original IOS 14. So there is some possibly that the Phonak hearing aid firmware software and Apple IOS have introduced some new issues.
I just hope the issue is resolved soon.
Ive just bought an Iphone 12 and have the same issue with Phonak Paradise 90R with crackling over bluetooth phone calls. What is the way forward here.
There’s no solution as far as I know. If you complain to Phonak they will send you back to Apple. If you call Apple then they will say the issue is with the Bluetooth device and send you to Phonak.
I’m making more calls with Zoom phone using the TV Connector with my MacBook.
As mentioned earlier. I have emailed Phonak and they said speak to my audiologist. I have also emailed Apple bug reporting on here:
https://www.apple.com/feedback/iphone.html
Also added a thread on the apple forum:
I had a similar problem with my Samsung S7, and recently with a Samsung A51 5G. The issue is
if you answer the phone, and it automatically transmits to your HA’s. Two audio and mic sources too
close together. If I am away from my cell, but in BT range, I just tap HA to answer phone…everything
is fine, no static.