Unfortunately you do not write which "HUAWEI MEDIAPAD 8" "you are using, there are several (T3, M5 ...)
I am using a "HUAWEI MEDIAPAD T3 10" with EMUI 5.1.3 (Android 7.0) The problem you are describing does not occur to me. The file "powergenius" is also present and active in my system.
I am using Primo 9.6.29.596752 and / or iGO World 9.18.27.736653.
Both are installed on the SD card and use a common "content" folder. Both work almost perfectly.
For me in my "Hymer" the optimal navigation device.