I'm not sure of the exact FW (i purchased of Ebay),
Why would you do that? all those Ebay firmware is nothing but rip off, most of them have dev fees and then you pay just to download it, all other reliable custom firmware are free to download you just pay dev fees 2-3% some are even dev-free.
I can not find the fan command line when i right click and inspect?
There is no command line, just edit this line
<div class="cbi-value" id="fan_ctrl" style="display:none">
to this
<div class="cbi-value" id="fan_ctrl" style="display:">
And hit Enter, the fan option will show and you set the fan speed once only.