Flashing the Bitstream
Once you have the gateware, it needs to be downloaded to the device. On the Pico-Ice the easy way to do this is with the dfu-util command.
dfu-util -a 1 -D gateware.bin
Where gateware.bin is the name of the gateware you are trying to download to the pico-ice.
If That Fails
Sometimes this does not work. Here is why. In that case a different approach is needed. The solution is to first convert the binary to a UF2 file format.
bin2uf2 -o gateware.uf2 gateware.bin
You can inspect it with uf2dump.
uf2dump gateware.uf2 > inspect.txt
more inspect.txt
Then put the pico-ice RP chip in a state to receive new gateware.
On Linux:
sudo picocom --baud 1200 /dev/ttyACM0
On Mac:
Flashing gateware to the Pico-Ice is not currently working on Mac OS.
If needed, delete the previous gateware.
rm -f /media/devel/pico-ice/gateware.uf2
And now you can install your new gateware by copying to the pico-ice usb drive.
cp gateware.uf2 /media/devel/pico-ice/
Another Approach
Another person uses this approach.
sudo picocom --baud 1200 /dev/ttyACM0
picotool uf2 convert <file>.bin <file>.uf2
picotool load <file>.uf2
picotool verify <file>.uf2
picotool reboot