Over-the-air firmware/filesystem upgrade process for 802.15.4
FOTA upgrade image file formats
Digi XBee® 3 802.15.4 RF Module User Guide
236
FOTA upgrade image file formats
OTA/OTB file
The .ota file extension represents a file which contains a FOTA upgrade image. The .otb file extension
represents a file which contains a FOTA combined upgrade image containing both the bootloader and
the firmware. However, the way the XBee 3 802.15.4 RF Module processes both the files remain the
same.
fs.ota file
The .fs.ota file extension represents an over-the-air MicroPython file system upgrade image. The XBee
3 802.15.4 RF Module processes these files differently as compared to OTA/OTB files.
The over-the-air file system upgrade process is explained in detail in
.
The OTA header
The FOTA uses a specific firmware file with a .ota extension. We recommend parsing the OTA header
from the OTA file first to obtain the firmware version, manufacturer code, image type and the size of
the GBL file. These parameters are required to generate the rest of the FOTA upgrade messages.
Note
All fields in the OTA header with the exception of the OTA Header String are in little-endian
format.
The format of the OTA header is:
Bytes Field name
Description
4
OTA upgrade file
identifier
Has to match 0x0BEEF11E in little endian. If it is not, then the OTA file
is not a valid upgrade file.
2
OTA Header version 0x0001
2
OTA Header length
Length of the OTA Header.
2
OTA Header Field
control
Bit mask that indicates if additional information is included in the
image. (Read the Security Credential Version in this table).
2
Manufacturer Code
0x101E
2
Image Type
0x0000 - OTA/OTB file
0x0100 - OTA file system image
4
File Version
The version of the firmware upgrade image.
2
Stack Version
This is set to 2 by default.
32
OTA Header String
Usually contains the Firmware image name followed by 0xFFs. For
example,
FFFFFFFFFFFFFFFlbg.10F3_42MD_3BX
which is XB3_DM24-
3F01.gblFFFFFFFFFFFFFFF in little endian
4
Image Size
Contains the size of the .gbl file for the firmware.
