To switch from 32-bit to 64-bit you will need:
a new uSD card of good quality, 32GB,
a USB stick, so that you can transfer copies from one OS to another, later copy the daily variables here.
a lot of patience, so that if you are unfamiliar with Debian, then do everything in order.
Yes and read, you will find how to do it in the wiki, if not, then ask.
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Gyula HA3HZ
HA3HZ