This is the latest Kernel`for your R4 and is updated on 24 June 2008.

R4 Ver 1.18 English Kernel (24-April-2008)

After english.zip is downloaded, please unzip it into a temporary
directory and copy the _system_ and moonshl folder and _DS_MENU.dat and _DS_MSHL.NDS to the root of your
microSD/TF card through the USB card reader.
You may place all your games in a Games folder on the root of your memory card.
Games must have a .nds extension.

Visit here for a step-by-step guide>>>