So if you want to watch a 1080 video on this device, the player will upscale it to 1242 and then the hardware will downscale it to 1080 again? or will there be some way to bypass all this?
This article concerns "rasterization": the process of converting a description of an image into actual pixels.
A 1080p video stream doesn't need rasterizing -- it already consists of pixels. Any sane video player would simply show the original 1080p video mapped on the 1080p screen in full screen mode.
Or put another way, when you play a video, you let the OS take over the full screen and there's no need for downsampling.
Its not like the downsampling is a permanent stage of some rendering pipeline to the display.