Amiberry and scanline mode in 6.1.1

[muki__83]

Hi. I want to activate scanline mode in A1200 system emulator by amiberry in Recalbox V 6.1.1.
I created the .uaeconf.uae file in the A1200 roms directory and edited it insert the value gfx_linemode=scanline
linemode=scanline but the scanlines are not activated, if I call the gui and activate them they work but if
I exit the game and restart it I lose the scanlines, I would like them permanent on all the games.
Thanks.