No Boot Camp at startup?

Hi,

I'm somewhat new to Mac but I have a 2020 Macbook Pro that I installed Win10 on through Boot Camp. Lately I've been using Win10 more often than OSX.

Not long ago I realized Touch to Click was not available in Win10 (I believe, but cannot confirm, that it was working when I first installed Win about 2-3 months ago) and saw a solution that said Boot Camp had to be updated through OSX. So I booted into OSX (holding down the option key) and saw that an update to the OS was available. I believe I was already on Big Sur 11.3, but this update moved me to Big Sur 11.3.1.

Since the update to 11.3.1, I can no longer get to Windows. Holding down the option key at boot does nothing, as if Boot Camp isn't there...but Boot Camp is there, because if I open it in OSX, it warns me that running Boot Camp Assistant will overwrite my Windows install.

So Windows is still there on its own partition, but Boot Camp will not start on boot. What can I do to fix this?

Thanks in advance for any hints to this mystery,

d