MegaDev9 v1.01 is released. MegaDev9 is a part of the PS2 that handles USB, HDD and Ethernet. In PCSX2, USB is handled by a USB plugin, HDD and Ethernet are handled by a DEV9 plugin. This plugin is a DEV9 plugin, so it's a plugin for HDD and Ehternet. At the moment, the plugin only handles HDD. Ethernet support will maybe come in the future.

MegaDev9 v1.01 Changelog:
-Reduced the IRQ timings
-The minimal HDD size is now 8 GBs, lower sizes seem to cause problems
-Implemented the Idle command
-Implemented the nIen bit in control reg (disables IRQ)
-Fixed a bug occuring when pressing Escape then running another HDD-compliant program in PCSX2
-Implemented the Sony-specific security control command (0x8E), the programs that want a Sony HDD should now work without a patch
-Changed a bit the Identify device command, maybe it will fix Final Fantasy XII.

Download: MegaDev9 v1.01
Source:Here