In the sys file in the [rawdisplay] section, by removing the semicolon in front of dpi, you will choose the appropriate resolutions

[rawdisplay]
driver="gles_2_0_android"
screen_xy="auto"
;base_dpi=240
;dpi=120
;dpi=160
dpi=240
;dpi=320
;dpi=480
;dpi=640

you have at least 240 as you can see