Off chip OAD for cc2650 with BLE stack 2.2

I am trying to do off chip OAD for simple_peripheral project.

Here are the implementation details:

Hardware Components:   CC2650em+Smart RF06 board

Software :BLE_STACK:  ble_sdk_2_02_00_31+ TI-RTOS: tirtos_cc13xx_cc26xx_2_18_00_03

Project: cc2650_lp \ simple_peripheral

IDE: IAR

I am following the "Over-the-Air Download User’s Guide For BLE-Stack™ Version: 2.2.0' .

I built the bim_extflash, simple_peripheral_app and simple_peripheral_stack projects as explained in section 8.2  Out of box demo (off chip OAD).

I also made the following changes to suit my needs:

I used the cc2650lp  code instead of cc2650em because the latter does not have an OAD_extflash configuration.I changed the board file to cc2650dk_5xd in preprocessor symbols.  

Also, I changed the configuration of the bim_extflash project to FlashOnly_ST.

Before using the merge.bat file ,I modified the script to read bim hex file from FlashOnly_ST folder.

I have the following issue:

I generated the all.hex and app_stack_oad.hex files using merge.bat,and i am able to load the all.hex (bim+app+stack) file successfully on the board.  But when I perform oad on BLE device monitor ,the download cancels immediately at 0%.

I get the error: 

Oad programming timed out.

WriteRSp[FFC1]:st=20 n=0

WriteRsp failed

Gap link Terminated: status=0 h=0 reason=0x08

SimpleBlePeripheral disconnected.

What could be the source of this issue? Do I have to change the locations of  bim,app and stack in the merge.bat folder? Have I overlooked something?

Please advise.