I used the MC exploit to do this, but if you have a slim ps2, then you will have to boot with dev1, if your chip has this option.
You can use the ulaunchelf that is working to move the files.
Load the ulaunchelf thats working
put the files BOOT.ELF (from ulaunchelf 4.06) and the USBAdvance.elf
(i use the 1 from this site) in a USB Pendrive
Use FileBrowser to copy BOOT.ELF to mc0:/BOOT (if theres no boot folder, you have to make it)
then copy the usbadvance elf there too.
Then after its copied, re-boot the PS2 in dev1 mode and the uLaunchelf 4.06 should load. Now you can select the usbadvance elf and assign it to a button or auto-load as default.
You can goto the tutorials page
for explainations on using the filebrowser to copy and make directories (folders)
I hope this helped, i dont have time to write a new tutorial as i dont know how your chip works.