@techokami @netbsd What dd command are you running on what OS? The blocksize (bs=...) parameter just controls how much gets written at a time, I usually use bs=$((8192*1024)) (8MiB) just to make sure I'll quickly fill kernel buffers and modest size caches if any exist on the device. The bs parameter should not effect what actually gets written to the thumb drive.

What machine are you trying to install to?

At the boot prompt what does devpath report? (I think that's the right option)