Patch for restoring functionality of Oreo-based roms (based on Oreo kernel, for example LOS 16.0) with updated Pie firmware of your device.
If you have already received Pie update and installed it (you have Pie firmware installed), then the current LOS 16.0 build based on Oreo kernel source code (or other Oreo-based roms) will not work correctly with Pie firmware of your device.
The main problem - there is no voice when calling.
I searched and tried different options for a long time to make this ROM work on a device with Pie firmware. But chose the easiest way at this moment.
After installing LOS 16.0 you need to replace
DSP partition on device from Oreo firmware.
For convenience, I wrote a small patch for TWRP. It already contains DSP.img from Oreo firmware (2.33.401.19).
Backup of your original partition with the name dsp.img.backup will be created on internal memory card after flashing this patch.
Don't delete this backup from card, you may need it to restore (or you can take this img from Pie firmware for your device)!!!
Second patch (if required) is restoration of your original dsp.img.backup from internal memory card into dsp partition.
I checked these patches myself before.
I think that 99% they are suitable for use with other custom Oreo-based ROMs (with Oreo kernel).
DSP_TWRP_Flashable_OREO_2.33.401.19_install.zip - install
DSP_TWRP_Flashable_restore_backup_from_sdcard.zip - restore
Enjoy your use!