So GrapheneOs (GOS) is now based on Android  11.  The default dialer provides Visual Voice Mail (VMM )  .  When GOS moved from Android 10 to 11 VMM quit working for me.  My carrier is Verizon Wireless in the USA.  This is my documentation for an attempt to fix this issue.

 

 

android version

build id operating system

proprietary binaries

src build or binary install

 

link to binary or src

 

does VMM work

 10  QQ3A.200805.001  graphene  android-prepare-vendor  src . signed release.    

 yes. able to lock bootloader.  no updates coming.  running it on daily driver

     graphene

used google method . 

src . testkeys

 

 

no. didnt see sim card. graphene process faile at end and had to manually flash phone

 

 11  RQ1A.201205.003.2020.12.12.03  graphene        
      android-prepare-vendor   choosecombo release aosp_crosshatch user  m  wouldnt boot.  I had used the alternate config file for vmm. plus had been playing with android prepare vendor to try to get a full one. need to try again