After changing the low speed fan(2000rpm), the speed can not be recognized
Are you sure you flashed the custom firmware (from the start page), as I removed this fan speed check.
To check if you flashed the custom firmware: go to the minerAdvanced.cgi page and you should see the voltage control settings
Can you write a correct flashed firmware step?why i flashed firmware for it and i can't finded the web page to change the voltage.the web page just have the frequency choices