http://msdn.microsoft.com/chats/transcripts/mobileembedded/06_1129_msdn_wince.aspx

David Kelley [MS] (Expert):
Q: Which is the difference between the nk.nb0 and nk.bin image created by PB5.0?
A: .nb0 files is a raw file format suitable for flashing ROM via a ROM programmer while the .bin file is a MS format we use to download images to the device via the bootloader. In the end, same information, different formats.

要产生NK.NBx文件，你必须在Config.bib中设置ROMSIZE参数。
如ROMSIZE＝02000000，设置NK.NB0的大小为32M，若Image的大小超过32M，则还会产生NK.NB1，NK.NB2……