This update fixes several bugs with the latest R4i patch. It also bypasses the latest Nintendo DSi firmware.
From GBAtemp: "The R4iDSN/R4iGold team has stated that the first firmware update they released to bypass DSi/XL firmware 1.4.2 (1.4.3 for China) was not tested thoroughly enough and can malfunction for users. The team states that if your cart bricks during the update process with the original update, you can attempt to re-flash and unbrick it it using the V142_Patch_NDSL.nds update file via the use of another flash cart, and an original DS or DS Lite. This is accomplished by booting the update on another flash cart, then swapping it for the R4iDSN/R4iGold before choosing to apply the update."