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Document Revision
Document number: 10551369
Release: Mar 20, 2015 10:12
Document version: 13


Bluetooth Low Energy Serial Port Module™ firmware, cB-2245, supporting Bluetooth Smart device development.

The firmware is valid for the following Serial Port Module™ models:

  • OLS425
  • OLS426

If you experience problems with your Serial Port Module™ please fill out an anomaly report and email it to

Current firmware version

Firmware Binary




"1.3.2 [20:07:00,Jan 22 2015]"

  • Bug fix bond management

Please remember to also update to the latest version of the Bluetooth Serial Port Adapter AT Commands and Serial Port Adapter Toolbox when updating the firmware.


Please see the Bluetooth Low Energy Serial Port Adapter - Getting Started guide to get started with the Bluetooth Low Energy Serial Port Module™.

Firmware upgrade instruction

The firmware of the OLS425 and OLS426 modules are updated using the connectBlue Flash Loader tool. Select the *.bin file when updating using the Flash Loader tool.

To change an OLP425 module into an OLS425 module the OLP425 can be flashed with the Bluetooth Low Energy Serial Port Module™ firmware, cB-2245. To flash the OLP425 the CC Debugger and the Smart RF Programmer tool from Texas Instruments is used. In this case the firmware *.hex file is required. The hex file includes a bootloader and once the hex file has been written to the OLP425 the firmware can be updated using the connectBlue Flash Loader tool. To request the *.hex firmware file please contact

Known Limitations and Notes

Power Consumption Stop mode
Current consumption in stop mode is too high in FW releases v1.1.0 and higher. We are working on a fix for this.
Bluetooth Low Energy Roles

OLS425/426 supports the peripheral role only and cannot be the initiator of a connection. However, directed advertisement was added in version 1.0.0 allowing for the peripheral unit to request a connection from a specific central unit. This means the OLS425/426 version 1.0.0 and later supports both Server-Peripheral role and Client-Peripheral role.

Warning! When directed advertisement is activated it will lock up the module CPU for 1,28 s, implying that the module is not receptive to any input during this time. If connect_scheme "always connected" is used, this means the module will be non-receptive for 1,28 s in each period of attempt. In this state, the module can for example not enter AT-mode.

Serial Settings

Warning! Baud rate 115200 kbit/s is not recommended. Transmitting data continuously at this rate may result in data loss.

Avertising and scan response data

For the v1.1.1 release the connectBlue Serial Service service UUID was added to the scan response data. It was added to the scan response data instead of the advertising data for backwards compatibility with earlier firmware versions. However, when a central device is using passive scan instead of active scan the central device will only see the advertising data and not the scan response data.

For example Apple recommends filtering on UUIDs when doing a scan in iOS apps and may use passive scan when the app is not active. This may require that the UUID is part of the advertising data instead of the scan response data.

Use the commands below to set the connectBlue Serial Service service UUID in the advertising data and set the device name in the scan response data:

At commandDescription

Set advertising data to:
Tx power: 4dBm [020a04]
128-bit Service UUIDs, complete list: connectBlue Serial Service UUID [110701d7e9014ff344e7838fe226b9e15624]


Set scan response data to:
Complete Local Name: OLS425 [07094f4c53343235] where
07 is the length of the data
09 is the AD type complete local name
4f4c53343235 is the name data
to set a different name change the length and name data fields 


Firmware Binary




"1.3.1 [09:29:53,Mar 18 2014]"
  • Bug fix regarding out-of-range behaviour
  • Bug fix regarding authentication and security


"1.3.0 [12:08:56,Jan 16 2014]"

  • Updated to TI BLE Stack v1.4.0
  • Added AT command AT*ADDIS for configuration of Device Information Service characteristics. For example manufacturer and model number can be configured


"1.2.0 [20:25:23,Nov 14 2013]"
  • Updated to TI BLE Stack v1.3.2
  • "Stay awake in AT mode" feature in AT*AMPSF command is ignored
  • Added 5s online period after reset if feature "Wake up on Dsr" is not enabled in AT*AMDS2 command


"1.1.1 [11:28:41,Oct 17 2013]"
  • connectBlue Serial Port service UUID added to scan response data. This makes it possible to filter on the Serial Port Service UUID when doing a scan in for example iOS or Android apps. Please see the notes section below for further information.
  • Device Info Service updated and aligned with OBS421
  • Bug fix AT*AGAD and AT*AGSD
cB-2245-04(fw_ols425_v1.1.0).bin1.1.0 [16:08:56,Jun 11 2013]

Note! This version of cB-OLS425/426 includes changes in the Serial Port Service protocol and is NOT backwards compatible. For communication with cB-OBS421, version 5.1.0 or later is required.

  • Modified Serial Port Service protocol
  • Faster connections
  • Added power saving features for optimization of typical Bluetooth Low Energy use cases, see Bluetooth Low Energy Serial Port Adapter - Getting Started. Please note that AT command AT*AMDS2 has been modified and is not backwards compatible.
  • Support for custom advertise data, see AT*AGAD and AT*AGSD in Bluetooth Serial Port Adapter AT Commands. This feature can be used together with cB-OBS421 (version 5.1.0 or later) as central performing an inquiry, AT*AGI.
  • Extended UART serial settings support
    • Baud rates 1200, 2400 and 4800 bits/s
    • 2 stop bits


1.0.1 [15:27:32,Mar 21 2013]

  • Increased default TX output power and RX gain


1.0.0 [11:35:46,Feb  7 2013]
  • Client functionality. The OLS425 can now initiate a connection to a central device using directed advertisement
  • Connection parameters like connection interval and advertising interval configuration using S-registers
  • Security modes


0.9.1 [08:08:12,Nov 27 2012]

Pre-release version 0.9.1