Cradle Double Image Mechanism - Motorola HC700-G User Manual

8.Cradle Double Image Mechanism

The cradle Flash memory contains two software images: the primary software image which is
upgradeable in the field, and a secondary image installed in the factory or Depot. The cradle secondary
image is a backup image used in case the primary image is damaged.
After cradle reset, the Boot Loader start running. The Boot Loader checks the primary image validity.
If valid, the cradle boots from the primary image. Otherwise, it will attempt to boot from the secondary
image.
The user will be notified by special system LED indication (see LED System states) that secondary
image is running, with this image the user should retry to program the primary image again.
Each software image has a unique valid tag programmed during image programming; it contains start
& end signature, image's checksum and image length.
The boot loader has 4 cases of boot decision:
Valid tag of primary image is correct & compatibility with image software, in this case boot loader
1.
boots from primary image (see Figure 104).
Valid tag of primary image isn't correct or damaged, while valid tag of secondary image is correct
2.
& compatibility with image software, in this case boot loader boots from secondary image (see Fig-
ure 105).
Both valid tag of primary and secondary isn't correct, damaged or not existed, in this case the boot
3.
loader tries to boot from primary image. If Primary image reside in the flash, the boot loader will
boot from it. (see Figure 106).
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Administering the 4 and 8 Bay Charging/Communication Cradles