Changing a creative in a playlist to be in portrait dimensions is not enough for displaying vertical playlists. You need the Android operating system to be rotated to portrait orientation mode. The following procedure will show you how to rotate your Android operating system in your Android device, using 2 phases: rooting your device and changing the screen rotation system properties. This was tested in Tronsmart MK908II. It might work in other Android devices and can save you the complicated process of flashing your device with custom firmware.
Installing the application:
1) Go to Google Play market.
2) Search for “ES3“. This is a file explorer application
(with light blue and white icon).
3) Install this application.
Rooting the device:
4) Run the ES3 application.
5) In the left menu, click “Tools”.
6) Scroll down and change the “Root Explorer” to on, in order to root the device.
Important: If it doesn’t let you change it to on, it means you won’t be able to root this device using the ES3. Instead you might need to download, install and run another rooting application (such as Kingo) or a super user application or flash the device with a custom rooted firmware.
Granting R/W permissions:
7) Click the “Root Explorer”.
8) In the menu, click the “Mount R/W”.
9) In the new settings window, change the setting of “/Path” and “/system” from “RO” to “RW” and click “OK” (this will grant you read/write permissions on
the system folders and files).
Changing the screen rotation properties:
10) In the left menu, click “Local”.
11) Click the “Device” option and you will see the root folder of the device.
12) Scroll down to find the “system” folder and then click it to enter.
13) Click the file “build.prop” and choose the “ES Note Editor” to edit it.
14) Scroll down and find the line “ro.sf.hwrotation=270”.
15) Click the top-right menu icon and from the menu choose the “Edit” option.
16) Now, when you’re in edit mode, change the number 270 to 180 (degrees of rotation).
17) Right-click on the screen to go back and the editor will ask you to confirm saving the properties file.
18) Choose “Yes”.
19) Unplug the device from the power and re-plug it (if it has a power button, you can just turn it off and then turn it on).
20) Now, it will boot when the Android operating system screen is rotated to portrait orientation mode.