r4 won't work on old DS lite any idea's

I've purchased two r4's one for a new ds lite both r4's work fine however on the older first issue of DS lite's get message no ds card inserted any idea's anyone

 

Try the paper shim trick first. It could be that the older NDSL's slot one contacts have become "sprung" and aren't making good contact.

Cut a piece of paper slightly narrower but longer than the R4. Put it on the non-contact side of the R4 and insert the R4 (with the paper on the back) into slot 1. It may increase the thickness of the R4 such that the slot 1 fingers now make contact.

 

many thanks that r4 now works fine