Rearrange the channel buffer sizes into three neat use-editable values in options.h. Increasing RECV_MAX_WINDOW gives big network performance increases - even with the present buffers (which haven't changed) it performs a lot better. Next step is to make the window size a cmdline option.

#!/bin/sh
exec 2>&1
exec dropbear -d ./dropbear_dss_host_key -r ./dropbear_rsa_host_key -F -E -p 22