Here is a tutorial to create a transparent/bridged AP with raspbian/debian/ubuntu distros:
*First we update everything:
sudo apt-get update
sudo apt-get upgrade
*Install hostapd and bridge utilities and we have to stop hostapd after it is installed:
sudo apt-get install hostapd bridge-utils
sudo systemctl stop hostapd
*Create bridge br0:
sudo brctl addbr br0
*Create a file /etc/hostapd/hostapd.conf
interface=wlan0
bridge=br0
#driver=nl80211
ssid=ADD-YOUR-SSID-HERE
hw_mode=g
channel=7
wmm_enabled=0
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=CreateYourPasswordHere123!!
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP
**or if you're using a wireless n NIC (I have an ath9 USB NIC)**
interface=wlan0
driver=nl80211
bridge=br0
ssid=ADD-YOUR-SSID-HERE
hw_mode=g
channel=7
ieee80211n=1
wmm_enabled=1
macaddr_acl=0
auth_algs=1
ignore_broadcast_ssid=0
wpa=2
wpa_passphrase=CreateYourPasswordHere123!!
wpa_key_mgmt=WPA-PSK
wpa_pairwise=TKIP
rsn_pairwise=CCMP
*Edit /etc/default/hostapd and change this (be sure to uncomment it too):
DAEMON_CONF="/etc/hostapd/hostapd.conf"
*Add eth0 to br0:
sudo brctl addif br0 eth0
*Edit /etc/network/interfaces and add this:
auto br0
iface br0 inet dhcp
bridge_ports eth0 wlan0
*Edit /etc/dhcpcd.conf and add this at the top of the file (above the other interfaces):
denyinterfaces eth0 wlan0
*And finally reboot... you now have a bridged/transparent wireless AP.
If you think you lost your AP, you can still connect to it via its hostname or IP, which you can obtain from your router/DHCP server by looking at at its leases