When a Windows Embedded Compact/CE OS is installed, three images are written to the device:
- xldr
- eboot
- nk, the OS image
When the OS is built, all three have different versions of their built code:
- .bin
- .nb0
- .exe
The first two are what are used when loading an OS or flashing a target device.
A bin file is a series of binary records that contain a sequence of binary (compiled) bytes as well as a memory location for that sequence of bytes. The data may be compressed. There is also overall header information (a TOC: Table of contents) for the file, usually positioned towards the end of the file. Viewbin (run in the VS/PB Build command line Release directory context) will display key information about the bin file:
An nb0 (nb zero) image is a complete raw uncompressed binary image of what is to be
placed in ROM. To that end, it will often be larger than a bin file as it has
to “fill in all of the gaps”.
In building the OS, various versions of eboot are built for different boot mechanisms. There is the NAND flash eboot (ebootnd), the SD eboot (ebootsd) and the UART boot (ebootUART). They are built both as BIN and NB0 files, the NB0 version used for direct flashing (or SD setup).
The main outcome of the OS build is the nk.bin file. This can be used for download and remote flashing. For direct flashing (via SD or application, see later) then an NB0 version of nk is required.
The OS can be downloaded at runtime from Platform Builder (as part of the Visual Studio IDE), run from external storage such as an SD card, or run from flash.
The OS images can be flashed in a number of ways:
- JTAG
- Via SD Card
- An OS runtime application (OSUpdate, ... NB0 file)
- Download (Platform Builder, CELoader, ... BIN file)
cfimager.exe tool is used to flash boot images and create FAT partition on SD/MMC cards
on the host PC for i.MX SOCs. The cfimager tool can only flash *.nb0 files, found in the release directory of the OSDesign
