Xfrom
XFROM is a DEV9 subsystem which consists of a memory card flash memory attached to the SPEED chip.
It is only used in a functional state inside the PSX. In the PSX, it uses the same chip brand and model that is also used inside normal memory cards. However, reverse engineering has shown that the driver for XFROM has code for handling chips with a capacity of 8, 16, 32, 64 and 128 MByte. Driver based on reverse engineering
SCPH-5xxxx consoles also have the drivers to access it (rom0:XFROMMAN & rom0:XFLASH) and the OSDSYS was updated to upload these drivers to the IOP and look for updates on XFROM following the same path convention that is used for memory card updates.
Yet, there are no known variants of the Network Adaptor containing the compatible variant of SPEED.