1

No root needed, just install Boldbeast Recorder and go, HTC One E8 dual sim can record calls perfectly in two sides.

There is a bug in the HTC One E8 ROM of Android 4.4.2 - Sometimes when the call is hung up the ROM doesn't notify the app. We found this bug in the ROM of HTC Desire 820 Android 4.4.4 also.

If you are using other recorders you'll see "the call is hung up but the recorder continues recording".
However Boldbeast Recorder can bypass the bug and detect the call state correctly, therefore works far more good and stable than other recorders.

2

Android 4.4 please use these settings to record calls:
- Record Mode: 4
- Tune Audio Effect: No
- Tune Audio Route: Group3

Android 5.x and 6.x please use these settings to record calls:
- Record Mode: 1 or 5
- Tune Audio Effect: No
- Tune Audio Route: Group3

No root needed, it records call perfectly in two sides.

3

HTC U11: HTC U11 Call Recorder
HTC 10: HTC 10 Call Recorder
HTC One A9: HTC One A9 Call Recorder
HTC One M9: HTC One M9 Call Recorder
HTC One M8: HTC One M8 Call Recorder
HTC One M7: HTC One M7 Call Recorder
HTC One E9: HTC One E9 Call Recorder
HTC One E8: HTC One E8 Call Recorder