有線で接続、間にハブ1つ、USBメモリなので参考にならないと思うけど
明日くらいにHDD探して試してみる

dd if=/dev/zero of=dummy.img bs=1M count=100

ftp> put dummy.img
local: dummy.img remote: dummy.img
227 Entering Passive Mode (192,168,10,1,98,67)
150 Accepted data connection
226-File successfully transferred
226 62.067 seconds (measured here), 1.61 Mbytes per second
104857600 bytes sent in 62 secs (1690.68 Kbytes/sec)

ftp> get dummy.img
local: dummy.img remote: dummy.img
227 Entering Passive Mode (192,168,10,1,47,86)
150-Accepted data connection
150 102400.0 kbytes to download
226-File successfully transferred
226 106.407 seconds (measured here), 0.94 Mbytes per second
104857600 bytes received in 106 secs (985.03 Kbytes/sec)