Hello,
I installed SM 1.7 64-bit a couple of days ago on RPI4 4Gb.
The mount (RST-135) and the main camera (ASI2600) do connect and work fine.
However ZWO EAF and ASI120MM guider camera do not connect and not working.
Same equipment works fine with SM 1.7 32-bit.
I usually have ZWO EAF and ASI120MM connected to ASI2600's USB HUB.
Tried connecting to a powered USB HUB and directly to RPI as well. No luck.