If you are prepared to loose the complete upper part of the screen, you can
1) try to modify in koreader\frontend\device\kobo\device.lua this part:
Code:
-- Kobo Aura HD:
local KoboDragon = Kobo:new{
model = "Kobo_dragon",
hasFrontlight = yes,
display_dpi = 265,
}
Add under the line "display_dpi = 265,"
Code:
viewport = Geom:new{x=0, y=400, w=1080, h=1040},
Change the values of y and h as you see fit (y+h=1440).
I did not try this myself.
2) Or you can modify vlasovsoft\cr3.sh (for Coolreader). I tried it on a Kobo Touch (w=600, h=800). As an example (see the attached image), I use only the lower halve of the screen. You would of course have to adjust the values for Aura HD.
Code:
#!/bin/sh
#exec cr3/cr3 -stylesheet $STYLESHEET
exec cr3/cr3 -stylesheet $STYLESHEET -geometry 600x400+0+400
You could do the same thing in launcher.sh too, but the button to launch Coolreader will be available anyway.