So I have successfully accessed the AD2PI on a R Pi 3 via wifi using the following steps. I can't vouch that every step is required, but at the end of the path, things are working. Thanks to all for various clues that got me there. I did a sudo reboot after almost every step below, but I don't think its really required until the end...
1. Start with the AlarmDecoder modified Raspbian build on SD card (via SDFormater and Win32DiskImager) connected directly to hardwire ethernet (would not boot on my system)
2. Replace start.elf with the version at the link provided above (
https://github.com/raspberrypi/firmware ... aster/boot) - now boots to command line.
3. Resize the partition using the raspi-config utility to take advantage of entire SD card space.
4. sudo apt-get update -to get package list updates (it did take multiple tries to get complete set of updates to 4.1.20 files (as of 3/30/16))
5. sudo rpi-update - to get firmware update
6. added missing files brcmfmac43430-sdio.txt and brcmfmac43430-sdio.bin to /lib/firmware/brcm - did this by copying files to SD card on Windows machine, and then sudo mv to /lib/firmware/brcm
7. sudo iwconfig wlan0 power off (stops wifi from shutting down when unused to save power)
8. sudo nano /etc/wpa_supplicant/wpa_supplicant.conf - to edit wifi config file:
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1
network ={
ssid="your network name here"
psk="your network password here"
}
9. sudo nano /etc/network/interfaces - make sure wlan0 is available with following lines in the file:
allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet dhcp
10. sudo reboot
11. sudo ifconfig - to verify wlan0 is now listed
12, access
https://alarmdecoder.local from another machine on the network
SUCCESS!