-snip- I think you'll need --list-gpus to see name of all your GPUs and then use multiple --gpu-names instead.
But it's for btcrecover while OP is utilizing "
seedrecover.py" script which doesn't use btcrpass.py but btcrseed.py.
In seedrecover, as of btcrecover v1.12, his options to use GPU is under "
OpenCL acceleration" when prompted for commands
seedrecover.py -h.
Here are the available args for seedrecover gpu acceleration:
github.com/3rdIteration/btcrecover/blob/master/btcrecover/btcrseed.py#L3204-L3210The developer has a note in the official documentation page that it's currently buggy.