If option 66 is configured on DHCP server it is not released
in debug I see: Unknown(66)=XX-XX-XX…
/ip dhcp-server
add address-pool=dhcp_pool0 disabled=no interface=VoIP name=dhcp1
/ip dhcp-server option
add code=66 name=option66 value="'tftp://195.93.169.172/\$mac.cfg'"
/ip dhcp-server network
add address=192.168.253.0/24 dhcp-option=option66 gateway=192.168.253.1
If I use code=43 or any other number works fine!
/ip dhcp-server
add address-pool=dhcp_pool0 disabled=no interface=VoIP name=dhcp1
/ip dhcp-server option
add code=43 name=option66 value="'tftp://195.93.169.172/\$mac.cfg'"
/ip dhcp-server network
add address=192.168.253.0/24 dhcp-option=option43 gateway=192.168.253.1
Tested in 6.47.10, 6.49.8 and also 7.X, no way.