which port on D7-2b is connected to ISP router? LAN 1 or WAN? if it is lan1, have you disable DHCP server on D7-2b? make sure there is no ip conflict. laptop to WiFi of D7-2b, internet works or not?...

This software can manage almost all tp-link powerline adapters(contains the wireless changing part): https://static.tp-link.com/resources/software/TL-WPA4220KIT_V1_Utility.zip About how to use this...

Try this: https://www.tp-link.com/us/faq-399.html

This router only support FAT/FAT32/NTFS format, you may check if the usb stick is running on these formats Big Dawg TE wrote I wonder if this has some bearing on why my TL-WR902AC won't recognize my...

Looks like a problem on WAN connection(PPP). You already have the main ISP router, "Connection Type : Dynamic IP" may be the solution for you. (not the PPPoE)

uninstall it in the control panel