<icon>
horizontal android, chest door open, exposing red triangle with exclamation point.

Android system recovery <3e>
r4275.1_FP2_gms69_1.9.3
 
Volume up/down to move highlight;
enter button to select.

reboot system now
apply update from ADB
wipe data/factory reset
wipe cache partition
reboot to bootloader
power down
view recovery logs
apply update from sdcard

Plugged USB cable results in dmesg:

[65653.044636] usb 3-1: new high-speed USB device number 25 using xhci_hcd
[65653.173731] usb 3-1: New USB device found, idVendor=2ae5, idProduct=9039
[65653.173738] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[65653.173741] usb 3-1: Product: Android
[65653.173744] usb 3-1: Manufacturer: Android
[65653.173747] usb 3-1: SerialNumber: f8c9f680
[65663.005036] usb 3-1: USB disconnect, device number 25
[68831.732542] perf interrupt took too long (2509 > 2500), lowering kernel.perf_event_max_sample_rate to 50000

Scrolling down and selecting option "apply update from ADB"
FP2 responds with same icon.
Text bottom of screen:

Now send package you want to apply
to the device with "adb sideload <file name>"

resulting dmesg:

[69031.019059] usb 3-1: new high-speed USB device number 26 using xhci_hcd
[69031.148680] usb 3-1: New USB device found, idVendor=18d1, idProduct=d001
[69031.148687] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[69031.148690] usb 3-1: Product: FP2
[69031.148693] usb 3-1: Manufacturer: Fairphone
[69031.148696] usb 3-1: SerialNumber: f8c9f680

Oppsie : ) Waited too long.

Now send package you want to apply
to the device with "adb sideload <file name>"...

Timed out waiting for package.

Installation aborted.

Reselecting option "apply update from ADB"

adb devices reports.

List of devices attached 
f8c9f680        sideload