Yes, I still have to have the ps1 disc, ($1.99 grab bin find) in my dvd drive, and I downloaded HDloader, and many of the other Elf's (like the media player, FTP server etc...) from Exploitstation for free, instead of buying a pressed version of HDloader.
Also, HDloader supports the same size drives as HDAdvance, you just need to get the patched version. there really is no difference between the two other than the graphics. (go check their forums for more info).
HDLoader IS directly bootable from both the HD AND the memory card, I have a 8MB memory card, and all that is on it is about 1mb for the exploit files, everything else, all the other elfs, HDloader, HDAdvance, and all the other apps reside on the HD in the boot partition.
With the new HDloader which contains the toxic .2 core, on boot the ps2 spins up the ps1 game for a few seconds, until the exploit triggers, then spins down. after that, its all HDD, no dvd usage at all (unless I throw in a dvd to watch, or a cd of MP3's). Copying new files and new versions of software over the the ps2 doesn't require a cd either, I just copy them onto a usb dongle, plug it into my ps2, and cut & paste from the launcher.
My total cost (sans HD) to get a fully open and customizable ps2 were $1.99 for a ps1 game, and $20 for a case of beer to share with a friend that had a mod chip to load the exploit onto my memory card, why would I want to fork out another $50ish, to only get HDloader, when I have so much more for so much less?
SD