Just wanted to share this.
My KM8P just upgraded to CE 8.90.4 and I noticed both menu and videos in kodi are shown bigger than my TV display (1080P) can show where some parts are beyond the edges of my TV display. So, I went ahead to Kodi’s Settings -> System -> Display -> Video calibration to adjust my TV display. So far, so good until I rebooted my KM8P. Upon coming back from a reboot, the problem persists where kodi is again shown bigger than my TV display (1080P) can show. In other words, the settings on previous video calibration is now lost after a reboot. So, I started searching for solution in this forum and found this post. Then, I followed a suggestion by aposhtol to change a refresh rate from 60 Hz to 59.54 Hz and now the video calibration setting sticks through a reboot.
I hope this will help others.