aros starts in 800x600 resolution as a default on ABI v1/x86_64 linux hosted.
If you change the screen resolution to 1024x768 and save it, the resolution gets changed correctly.
On the next start/boot of AROS, the window/screen is only some 100x100 pixels big. There is no way to use the screenmode prefs program to correct this, as the screen is too small to reach any buttons.
Deleting screenmode.prefs solves the problem and brings you back to 800x600..
Seems not restricted to 64 bit:
Windows hosted ABI1 and the 68k (v1) build seem to suffer, too
(http://aros-exec.org/modules/newbb/viewtopic.php?topic_id=9396)
ARSO-Dev list:
Von: "To-- Wi--n" twi--n@wi--e.net
Datum: Mi, 28.10.2015, 19:56
"I get similar issue on m68k after quick-hack-fixing my previously
reported issue (ScreenModePrefs allocation without initializing it,
setiprefs.c), resolution changes won't work, selected resolution gets
replaced with used gfx hidd's supported min resolution."