DFU in hrm example not 100% working

[Rbai]

I am using SDK11 on a nRF52 board. I had some success in DFU, but also had issues.

Was able to upload the bootloader successfully using Master control panel. But it always fail to upload softdevice or softdevice+bootloader. It would start transmission, then stop in random percentage. Was able to upload HRM with DFU application couple of times but it can also fail in the middle of uploading.

My steps.

1. erase flash
2. program s132 softdevice with nRFgo studio
3. build examples\dfu\bootloader\pca10040\dual_bank_ble_s132 and flash it
4. use master control panel to connect to DfuTarg
5. upload the prebuilt examples\dfu\ble_dfu_send_hex\test_images_update_nrf52\dfu_test_bootloader_b_s132.zip successfully
6. connect to DfuTest
7. upload dfu_test_app_hrm_s132_w_dfu.zip successfully with several tries
8. connect to Nordic_HRM
9. upload dfu_test_softdevice_b_s132.zip or dfu_test_softdevice_w_bootloader_b_s132.zip always fail

[Rbai]

No, I did not change any code. Do I need to do something to disable the watchdog?