Artesyn MVME4100ET Single Board Computer Installation and Use (June 2014) - Manual (Page 108)

MOTLoad Firmware
MVME4100ET Single Board Computer Installation and Use (6806800K76F) 108
POST images are expected, but not required, to return to the boot loader. Upon return, the
boot loader proceeds with the scan for an executable alternate boot image. POST images that
return control to the boot loader must ensure that upon return, the state of the board is
consistent with the state that the board was in at POST entry. USER images should not return
control to the boot loader.
6.7.5 Alternate Boot Images and Safe Start
Some later versions of MOTLoad support alternate boot images and a safe start recovery
procedure. If safe start is available on the MVME4100ET, alternate boot images are supported.
With alternate boot image support, the boot loader code in the boot block examines the upper
8 MB of the flash bank for alternate boot images. If an image is found, control is passed to the
image.
6.7.6 Boot Image Firmware Scan
The scan is performed by examining each 1 MB boundary for a defined set of flags that identify
the image as being POST, USER, or Alternate MOTLoad. POST is a user-developed Power On Self
Test that would perform a set of diagnostics and then return to the boot loader image. USER
would be a boot image, such as the VxWorks bootrom, which would perform board
initialization. A bootable VxWorks kernel would also be a USER image. Boot images are not
restricted to being 1 MB or less in size; however, they must begin on a 1 MB boundary within
the 8 MB of the scanned flash bank. The flash bank structure is shown below:
Address Usage
0xFFF00000 to 0xFFFFFFFF Boot block. Recovery code.
0xFFE00000 to 0XFFFFFFFF Backup MOTLoad image
0xFFD00000 to 0xFFDFFFFF First possible alternate image
0xFFC00000 to 0xFFCFFFFF Second possible alternate image
.... Alternate boot images
0xFF899999 to 0xFF8FFFFF Bottom of flash (flash size varies per product)