How to get .nb0 file from .img file

[markyoung]

As everybody knows ,we can flash ROM by SD card.But there is problem,where is .NB0 file.After several day's study I found the way .
All I study is about A04 Chs ROM(R130437.exe).The include two part,first is Bootloader,second is ROM.I think,two part should seperat at 01002f4.(why,I found it by ollyice.)
Each part also have two section first is header ,second is body,between two section is a lot of "0"(about 30H byte).So,after the "0"is the nb0 file ,NO.DELL is not stupid.
the file should be reverse ,(end be begin,begin be end,every byte turned)and XOR with somthing.with what ,XOR with from 80H to 100h(80H long),after you do this you may find you got the NB0 file.(99% similar).the 1%,still not know ,I will work harder.
My program is not very well,I want someone write a little program, first reverse file A,then use file b to xor file A repeatly.then ouput it to file C.

[aid]

Is this for the X50 or x51?
Did you reverse the Enterbootloader program?