Can't enter capital letters on Streaming Stick Plus

I recently switched to Spectrum, and installed the SpectrumTV app on my Roku Streaming Stick Plus. Spectrum REQUIRES a capital letter in a password, but when I got to the password entry dialog, the interface on the Stick+ shows nothing but a horizontal row of letters (also a space and and a backspace), plus 3 buttons that let me choose Numbers ("123"), Letters ("ABC") or Special Characters (!#$, or whatever). No provision for entering a capital letter. 

My other ROKU has a different interface for entering a string, with an Up/Lower Case button, so there's no problem with such a password restriction.

I contacted Spectrum, but (surprise!) they weren't willing to change their password restrictions for one customer. At first, I blamed Spectrum for the problem, thinkin that the alphanumeric entry interface was their issue, but when I used the other Roku to navigate to the same password entry dialog, and saw that the interface was peculiar to the device, I realized that Spectrum was only using whatever password entry interface supplied by the underlying Roku device.

Any suggestions? I would be astonished to learn there was no way to enter capital letters on the Stick+, and this may be cockpit error, but I could find NO way to switch to capitals on the Stick+.