Word of warning - you should really never flash over wifi
As for a repeater bridge, these are my settings:
Setup / Basic Setup:
Connection Type: disabled
Local IP Address: 192.168.2.201
Subnet mask: 255.255.255.0
Gateway: 192.168.2.1
Local DNS: 192.168.2.1
Setup / Advanced Routing:
Operating Mode: Router
Wireless / Basic Settings:
Wireless Mode: Repeater Bridge
Wireless Network Mode: <as per your wifi>
Wireless Network Name (SSID): <as per your wifi>
Wireless Channel: <as per your wifi>
Channel Width: <as per your wifi>
Wireless SSID Broadcast: Enabled
Network Configuration: Bridged
Wireless / Wireless Security: <as per your wifi>
Services:
DNSMasq: Disabled
Security:
Untick Block Anonymous WAN Requests (ping) and Filter IDENT (Port 113) then - SPI Firewall: Disabled
That *should* be the minimum of what you need to do. Obviously your IP settings will differ depending on your setup.