Even the "old" is new to me! I only recently discovered INDI and first plugged my Pentax K-1 to it a couple of days ago. As far as I've been able to work out, this camera isn't supported by libgphoto2 and the Ricoh API which should let me use PTP mode is not available in ARM64. To be honest I'm not sure what I'm missing out on with either of those but I was happy enough to get it working with the "new?" indi_pentax driver and MSC mode.
I hope you get your K5 working back the way you liked.
If "Pentax believes in the future of SLR photography", I hope Ricoh believes in the future of ARM architecture grin.png