@ leforban - which FTP server do you use? I use the one from https://www.ghielectronics.com/community/codeshare/entry/836
and I have tried the upload on new 4.3.7.10 with G400 and ENC28 module ad the upload speed is cca. 50-60kB/s (it was about 8kB/s on previous version) so there is quite big improvements. Download (reading) is faster - about 100kB/s.