ok i was stuck with the loading screen after upgrading the the kernal (system folder, moonshl folder, ds menu.dat file, ds_mshl.nds file in the file i downloaded from the r4 website it also included a file called ds_menu.ini. I tried to load the r4 cartridge and got stuck on the loading screen, I have a standard non HC sd card 2gb. this was version 1.20.

After reading this I downloaded R4DA version 1.18 Patched.rar. which upon extracting the files from the .rar folder i saw that it did not include the file called ds_menu.ini. Only containing the following

_system_ (folder)
moonshl (folder)
ds_menu.dat
ds_mshl.nds

so I copied these 4 onto my micro 2gb sd card, and deleted the ds_menu.ini file. Put the micro sd card into my R4 cartridge slapped it into the back of the ds lite thinking ok this don't work must be a connection problem with the sd to cartridge or its corrupted somehow.
Powered up the ds lite and voila loading then the r4 menu opened up.

Hope this helps seems the ds_menu.ini file causes a problem with some versions of the r4 cartridge.