Does anyone have a fairly recent version of 3Com Boot Services?

We have a copy which is about 3 years old, and the file we need is UNDIP.COM , which is a generic file for network booting. (I think !)
I am hoping that there is a more up to date version of this file, which will work with our network cards. (Realtek 8139)

If anyone knows where I can get an updated version of this file, please let me know.