Did you take the internal HDD, attach it to a USB adapter/enclosure and try to use it with OPL/PS2ESDL? If so, this is impossible as the DEV9 interface uses Sony's APA partitioning scheme while the use of USB drives requires FAT32 formatting. You'll need to either extract the game images from the HDD using WinHIIP, or go back and re-rip your original discs to ISO form (and games that are larger than 4GB will need to be "installed", OPL supports USBAdvance-style installation in 1GB chunks, while PS2ESDL supports that as well as SP193's own PS2ESDL format in 1.74GB chunks).
Chip-free/MC-free homebrew <3
FMCB 1.93 on MC for emergencies, NA
250GB HDD/FHDB 1.93/OPL 0.9.2 (GSM and non-GSM)/PS2 games, NO HDDOSD
80GB HDD/FHDB 1.93/POPStarter rev12/OPL644/GSM0.37/PS1 games, NO HDDOSD
SCPH-75001 (sitting idle, slims suck):
FMCB 1.92 on MC