This is with reference to your e-mail dated with Subject line : "Unable to select UPI".
Please note the issue could be on
Android 10 version (Dual SIM) devices which currently doesn't support UPI Payments on our mobilebanking app.
The same is getting fixed in the next App update. Until then we request you to try linking the account on our below partner UPI Apps which are powered by HDFC Bank.
Google Pay (Available on Android & iOS)
Mobikwik (Available on Android & iOS)
Justdial (Available on Android & iOS)
realme PaySa (Available on Android only).