Composite monitor on Raspberry Pi

Hi,
Was redirected here after a post on Raspberri Pi Forum, so I jave just a big question to make,

I never used RiscoOS before, but having read the announce of the availability of a ready to use SD image I downloaded it and tried.

I’ve the Pi connected to a standard definition monitor via the composite cable, and when I first started the image I got a barely readable screen, with tiny laqbels. I somewhat managed to get a setup screen, and reduce the resolution to 640×480, so all was totally readable, but whit the screen not totally visible due the overscan.

I modified config,.txt enabling the overscan, and i got again the unreadable screen with tiny labels, but worst of all the mouse was not working correctly: the pointer could be moved outside the desktop screen, clicks appeared to do nothing but using the right buttom made clear that the mouse position was read with an offset.

this is the config.txt I tried:
with disable_oversca=1 the mouse work.

==

	
uncomment this if your display has a black border of unused pixels visible
	
and your display can output without overscan

disable_overscan=0


	
uncomment the following to adjust overscan. Use positive numbers if console
	
goes off screen, and negative if there is too much border

#overscan_left=16

#overscan_right=0

#overscan_top=16

#overscan_bottom=16

#sdtv_aspect=1

#colour burst is disabled

#sdtv_disable_colourburst=1
#framebuffer_width=720

#framebuffer_height=576
sdtv_mode=2
fake_vsync_isr=1

kernel=riscos.img

to quickly get a sensible screen. press F12 and type
wimpmode 28
then press return a couple of times
this should get a mode you can use.

I’ve been having a look at this too.
With my setup, using video out into scart on tv, there is no need to do anything with config.txt.
It should boot up ok.
Following the instructions from Jess above, I get a usable screen, but the top and bottom go slightly out of view. Lose just under half a window title bar at the top.

I find this is worse if I select 800×600 from the monitor icon next to the raspberry.

If I try to correct this, using overscan_top=16 and overscan_bottom=16 in the config.txt, the mouse pointer is offset from where it actions, so leaving it alone for now.

You will also miss out four items on the pinboard that are now out of view.

1. The welcome file is one of these. This can also be found by clicking the blue SD card, then Documents, Welcome, welcome/html.

2. Configuration options can be found by opening SD card, then double click !Boot.

3+4. !PackMan and !Store can be found from Apps on the iconbar.

You will also miss out four items on the pinboard that are now out of view.

Menu on one of the Icons you can see. Select All (with right button, so menu stays put) Then selection > tidy

when you have it how you want you can then save a pinboard file. (into !boot.choices.boot.predesk iirc)

Thanks for the answers: wimpmode 28 does the trick: now I can read the screen.
The mouse offet remains, but I’ve discovered for pure chance that pressing the escape key during the boot sequence put me in a sort of safe mode in 640×480 resolution, where the mouse offset isn’t present.