DSTTi support Nintendo 3DS V2.1.0-4 and DSi V1.4.3 successfuly !
As well as know, The DSTT and DSTTi TTMenu Kernel have updated its lasted official kernel DSTT TTMenu V1.18 on Dec 15th, 2010. A Closed-Source firmware is also under active development, called YSMenu. It is programmed by Yasu Software with latest YSMenu V6.73 on 10th Jan , 2012. But both of them don’t support 3ds & dsi v1.4.3 .
There is a unofficial patch for the DSTTi for it to work on the DSi V1.4.3 and 3DS 2.1.0-4. please notice : The patch is only for dstti made by ndstt.com /ndstt.net . please download the below DSTTi upgrade patch and DSTTi Firmware (English).
Download: DSTTi Upgrade Patch