OnePlus 8 Sprint/T Mobile 10.5.20.IN55CB update fail via OnePlus 8 T-Mobile

  1. E1600306551484 , via OnePlus 8 T-Mobile , Sep 21, 2020 :
    Since getting the 10.5.20.IN55CB update, I basically cannot make any outgoing phone calls. The VoLTE and VoWIFI will not work and those features had to be disabled by the carrier. According to Sprint/T Mobile's website, a fix is not expected until 9/26/2020. That will be 3 weeks of a phone that doesn't work properly.


    OnePlus's customer service is a joke. My calls got disconnected 4 times before I got through to someone who I thought would help. I told her the problems and asked if my phone could be down graded to a previous firmware. She told me it was possible but I'd have to respond to an email from her with my personal information to get the process started. After giving my full name, address and email...I received a return email saying that a down grade was not possible and have since been bombarded with spam email on that account.

    I bought Samsung flagship phones for years before deciding to try OnePlus and truly regret the decision. The problem with the update and subsequent interactions with customer service leave me feeling like I've been scammed.

    There is nothing that will be done to help with this problem until OnePlus decides to fix their software and I just wanted to let other users know this is a known problem now and the customers are getting screwed.



  2. S1595515134984 , via OnePlus 8 T-Mobile , Sep 21, 2020 :
    You are not alone. This affected all Sprint OnePlus 8 users. I had same problems as you with OnePlus support. They eventually did remote into my computer and try to fix the phone but were unsuccessful. You can downgrade the phone yourself like I did using the below instructions. Sprint is more to blame as they refused to acknowledge any problem existed for weeks.


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  4. Q1600788714450
    Cupcake Sep 22, 2020

    Q1600788714450 , Sep 22, 2020 :
    I have this problem using the OnePlus 8 5G on Sprint. Outbound calls will disconnect on my phone after 2 rings. The called number will continue to ring until they answer my call. If they don't answer after 10-seconds, the call will stop but start back up again for another 10-second ring session. This will continue until the called number answers my call. If the called number answers my call within two rings that my phone makes, then there are no problems at all.

    A temporary workaround that worked for me is to do the following:

    1) Go into Settings
    2) Tap on Wi-Fi & Network
    3) Tap on SIM & Network
    4) Tap on Preferred network type
    5) Tap on 3G (CDMA / EVDO / UMTS / HSPA)

    By doing this, I'm able to make the outbound calls. When my call is complete, I'll go back into the preferred network type and set it back to "Automatic" because 3G is so slow and it also affects my inbound calls.

    I hope the fix on 9/26 fixes this issue because I just bought the phone and I'm in the 30-day return window.

    E1600306551484 likes this.
  5. E1600306551484 , via OnePlus 8 T-Mobile , Sep 27, 2020 :
    Sprint did something on their end to disable the VoLTE on my service. And I can make calls but I can't use data while calling. They had me go into settings and search "reset", click on the one for "network, wifi and Bluetooth" and reset it. It's 19:38 on 9/26 still no update available yet. Sprint and OnePlus are really screwing the customers and neither seems to care about it.


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  7. S1595515134984 , via OnePlus 8 T-Mobile , Sep 27, 2020 :
    They triggered a different bug by killing VoltE. Doing those steps disables 5g also. If you update profile it will undo those settings changes you just did.

    E1600306551484 likes this.
  8. E1600306551484 , via OnePlus 8 T-Mobile , Sep 27, 2020 :
    I found that out the hard way. Luckily resetting the network and power cycling the phone removed the VoLTE again. I hope they fix this soon because I was loving this phone before the update. It's such a clean, bloatwear-free device.

  9. mojoyoyo77
    Assistant Head Moderator Assistant Head Moderator Sep 27, 2020

    mojoyoyo77 , Sep 27, 2020 :
    "corrective software to resolvethis behavior and should bedeployed on 9/26/2020Do not exchange or factory datareset devices as the issue mayrecur until the fix is available".

    Yesterday was 09/26, I guess if the update hasn't started rolling out, it will be very soon

    E1600306551484 likes this.
  10. E1600306551484 , via OnePlus 8 T-Mobile , Sep 28, 2020 :
    1601259901775.jpg said:
    I just got the new update 10.5.21
    Seems all VoLTE and wifi calling is working but the data speeds are crap.
    5G upload 3.26 Mbpsdownload 0.17Mbps
    4G upside 7.71Mbps download 0.08Mbps
    Home internet through Spectrum upload 99.4Mbps download 11.3Mbps
    Immediately after update I had no signal so I used the phone keypad to re-active the phone, updated profile and prl, then booted into recovery to wipe the cache. Everything works after that.
    Hope this is the fix we need and the phones go back to working properly. Might try updating prl again to see if it helps data speeds.

    mojoyoyo77 likes this.
  11. E1600306551484 , via OnePlus 8 T-Mobile , Sep 28, 2020 :
    I was wrong about the data speeds. This morning when I left my house, the speeds dramatically increased.

    5G download 76.4Mbps upload 12.7Mbps

    4G download 20.8Mbps upload 8.04Mbps

    Seems like my phone is back to running great.



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  13. TwistedLayers , via OnePlus 8 T-Mobile , Oct 1, 2020 :
    $ speedtest-cli
    Retrieving speedtest.net configuration...
    Testing from T-Mobile USA (xx.xx.xx.xx)...
    Retrieving speedtest.net server list...
    Selecting best server based on ping...
    Hosted by GTT.net (New York, NY) [12.03 km]: 39.043 ms
    Testing download speed................................................................................
    Download: 114.68 Mbit/s
    Testing upload speed......................................................................................................
    Upload: 15.34 Mbit/s

    Indoors consistent!

    Still on 10.5.20
    I guess the. 21 update was for only Sprint users.
    Last edited: Oct 1, 2020

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