Hi, on this one, you can only lock the entire keyboard not halfs ;-(
If half isn't working you will need have that serviced or replaced.
If you want a new exact replacement remote for the best price please visit this site:
I wish I have better news for you but then this happens on this remote, there is a failed electronic component inside, not user replaceable due its surface mount size and parts availability.
In any case, I will stick with you until this is complete.
Please rate my service kindly.
Also it is the only way I am credited for my time and expertise with you.
Once you rate, I will be notified and will add your question to my priority list so you can reach me anytime until this problem is solved.
Then you can reach me by simply replying to this message anytime.
Thank you and have a great weekend!