Thank you so much for looking at my setup. You are correct, the rounded white jumper is from RST to GND per the instructions for RFM69. I have pasted the output from the additional configuration parameters you gave - I don't see any additional debug messages. I attached the tail syslog at the end of the post and it looks identical (but my eyes might be failing, honestly).
One note I wanted to add - I have two of these Adafruit radios and have swapped them to make sure that I just didn't have a bad unit. Neither works. And another thing - I used a separate power source that I know provides clean 3.3 (entirely separate from the Pi, power directly to the radio), and the results didn't change.
Again, thank you so much for your time!
pi@mysensorsgw:~/MySensors $ ./configure --my-transport=rfm69 --my-rfm69-frequency=915 --my-is-rfm69hw --my-gateway=mqtt --my-controller-ip-address=127.0.0.1 --my-mqtt-publish-topic-prefix=mysensors-out --my-mqtt-subscribe-topic-prefix=mysensors-in --my-mqtt-client-id=mygateway1 --my-leds-err-pin=12 --my-leds-rx-pin=16 --my-leds-tx-pin=18 --extra-cxxflags="-DMY_DEBUG_VERBOSE_RFM69 -DMY_DEBUG_VERBOSE_RFM69_REGISTERS"
[SECTION] Detecting target machine.
[OK] machine detected: SoC=BCM2837, Type=rpi3, CPU=armv7l.
[SECTION] Detecting SPI driver.
[OK] SPI driver detected:BCM.
[SECTION] Gateway configuration.
[OK] Type: mqtt.
[OK] Transport: rfm69.
[OK] Signing: Disabled.
[OK] Encryption: Disabled.
[OK] CPPFLAGS: -DMY_RADIO_RFM69 -DMY_RFM69_NEW_DRIVER -DMY_GATEWAY_LINUX -DMY_GATEWAY_MQTT_CLIENT -DMY_DEBUG -DLINUX_SPI_BCM -DLINUX_ARCH_RASPBERRYPI -DMY_DEFAULT_TX_LED_PIN=18 -DMY_DEFAULT_RX_LED_PIN=16 -DMY_DEFAULT_ERR_LED_PIN=12 -DMY_MQTT_CLIENT_ID="mygateway1" -DMY_MQTT_SUBSCRIBE_TOPIC_PREFIX="mysensors-in" -DMY_MQTT_PUBLISH_TOPIC_PREFIX="mysensors-out" -DMY_CONTROLLER_IP_ADDRESS=127,0,0,1 -DMY_IS_RFM69HW -DMY_RFM69_FREQUENCY=RFM69_915MHZ
[SECTION] Detecting init system.
[OK] Init system detected: systemd.
[SECTION] Saving configuration.
[OK] Saved.
[SECTION] Cleaning previous builds.
[OK] Finished.
pi@mysensorsgw:~/MySensors $ make
<removed all the compilation messages - if they would be helpful I can re-add them>
pi@mysensorsgw:~/MySensors $ sudo ./bin/mysgw
Jul 12 08:14:57 INFO Starting gateway...
Jul 12 08:14:57 INFO Protocol version - 2.3.2-beta
Jul 12 08:14:57 DEBUG MCO:BGN:INIT GW,CP=RPNGL---,FQ=NA,REL=5,VER=2.3.2-beta
Jul 12 08:14:57 DEBUG TSF:LRT:OK
Jul 12 08:14:57 DEBUG TSM:INIT
Jul 12 08:14:57 DEBUG TSF:WUR:MS=0
Jul 12 08:14:57 DEBUG !TSM:INIT:TSP FAIL
Jul 12 08:14:57 DEBUG TSM:FAIL:CNT=1
Jul 12 08:14:57 DEBUG TSM:FAIL:DIS
Jul 12 08:14:57 DEBUG TSF:TDI:TSL
Jul 12 08:15:07 DEBUG TSM:FAIL:RE-INIT
Jul 12 08:15:07 DEBUG TSM:INIT
Jul 12 08:15:07 DEBUG !TSM:INIT:TSP FAIL
Jul 12 08:15:07 DEBUG TSM:FAIL:CNT=2
Jul 12 08:15:07 DEBUG TSM:FAIL:DIS
Jul 12 08:15:07 DEBUG TSF:TDI:TSL
Jul 12 08:15:17 DEBUG TSM:FAIL:RE-INIT
Jul 12 08:15:17 DEBUG TSM:INIT
Jul 12 08:15:17 DEBUG !TSM:INIT:TSP FAIL
Jul 12 08:15:17 DEBUG TSM:FAIL:CNT=3
Jul 12 08:15:17 DEBUG TSM:FAIL:DIS
Jul 12 08:15:17 DEBUG TSF:TDI:TSL
^CJul 12 08:15:19 NOTICE Received SIGINT
Just in case
Jul 12 08:29:51 mysensorsgw systemd[1]: Started Session c3 of user pi.
Jul 12 08:30:15 mysensorsgw mysgw: Starting gateway...
Jul 12 08:30:15 mysensorsgw mysgw: Protocol version - 2.3.2-beta
Jul 12 08:30:15 mysensorsgw mysgw: MCO:BGN:INIT GW,CP=RPNGL---,FQ=NA,REL=5,VER=2.3.2-beta
Jul 12 08:30:15 mysensorsgw mysgw: TSF:LRT:OK
Jul 12 08:30:15 mysensorsgw mysgw: TSM:INIT
Jul 12 08:30:15 mysensorsgw mysgw: TSF:WUR:MS=0
Jul 12 08:30:15 mysensorsgw mysgw: !TSM:INIT:TSP FAIL
Jul 12 08:30:15 mysensorsgw mysgw: TSM:FAIL:CNT=1
Jul 12 08:30:15 mysensorsgw mysgw: TSM:FAIL:DIS
Jul 12 08:30:15 mysensorsgw mysgw: TSF:TDI:TSL
Jul 12 08:30:25 mysensorsgw mysgw: TSM:FAIL:RE-INIT
Jul 12 08:30:25 mysensorsgw mysgw: TSM:INIT
Jul 12 08:30:26 mysensorsgw mysgw: !TSM:INIT:TSP FAIL
Jul 12 08:30:26 mysensorsgw mysgw: TSM:FAIL:CNT=2
Jul 12 08:30:26 mysensorsgw mysgw: TSM:FAIL:DIS
Jul 12 08:30:26 mysensorsgw mysgw: TSF:TDI:TSL
Jul 12 08:30:36 mysensorsgw mysgw: TSM:FAIL:RE-INIT
Jul 12 08:30:36 mysensorsgw mysgw: TSM:INIT
Jul 12 08:30:36 mysensorsgw mysgw: !TSM:INIT:TSP FAIL
Jul 12 08:30:36 mysensorsgw mysgw: TSM:FAIL:CNT=3
Jul 12 08:30:36 mysensorsgw mysgw: TSM:FAIL:DIS
Jul 12 08:30:36 mysensorsgw mysgw: TSF:TDI:TSL
Jul 12 08:30:40 mysensorsgw mysgw: Received SIGINT
