Surely i have tested the code.

I expected you should see different behavior with that modification. 

I agree with you that this behavior (UF keep firing after CNT count to zero ) looks a bit strange. I also admit that the timer is not documented well. But it is hard to say there is silicon bug based on current founding. 

I could continue checking internally if this is expected behavior and get back to you.

Surely i have tested the code.

I expected you should see different behavior with that modification. 

I agree with you that this behavior (UF keep firing after CANT count to zero ) looks a bit strange. I also admit that the timer is not documented well. But it is hard to say there is silicon bug based on current founding. 

I could continue checking internally if this is expected behavior and get back to you.

Not really what I expect from using a hardware peripheral.

No, ' behavior don't  follow what your expected ' could NOT prove silicon bug.

If you see abnormal behavior (not you have expected), could you upload the code that could reproduce the issue.

Not really what I expect from using a hardware peripheral.

No, ' behavior don't  follow your expected ' could NOT prove silicon bug.

If you see abnormal behavior (not you have expected), could you upload the code that could reproduce the issue.

Not really what I expect from using a hardware peripheral.

No, ' behavior don't  follow your expectations ' could NOT prove silicon bug.

If you see abnormal behavior (not you have expected), could you upload the code that could reproduce the issue.

Not really what I expect from using a hardware peripheral.

No, ' behavior don't  follow your expectations ' don't prove silicon bug.

If  you are looking for the UART part of code that the CDC example used, you may get cdc.c/h files  in folder like below:

C:\SiliconLabs\SimplicityStudio\v4\developer\sdks\gecko_sdk_suite\v2.7\hardware\kit\common\drivers

Sorry I have not catch your point.

Do you mind to elaborate you use scenario as detailed as possible.

I don't understand how you related the SWD/bootloader  with EBI.

what SDK you have installed?

do you mind to upload a screenshot 

You can start with example here:

https://www.silabs.com/community/mcu/32-bit/forum.topic.html/new_32-bit_periphera-hpNV.html

These example only use low level emlib.