Our engineer who is responsible for research and development has find out the solution to solve some small bugs for doogee phone, the method is as follow:

Proximity fix (black screen after call ends for 3-4 seconds)

Open build.prop (inside /system) and on the end of the file add the following lines

ro.lge.proximity.delay=25
mot.proximity.delay=25

Low speaker volume during calls

Open engineer mode (on the dialer press *#*#3646633#*#* )
move to Hardware Testing tab (third on the right)
then to Audio
select Normal Mode
for Type: spf and spf2
and for each level (from 0-6) increase the values and press set each time
tip... for level 6 set 150 or at maximum 155 but not the maximum available 160.

When finish go back on menu Audio
Select SpeechEnchacement
Change common parameter to Normal mode
Change parameter0 to parameter6
Set a value around 300
And for parameter7
Set value between 96-124

Even though you don’t need to restart the phone its better to do.