Testing out sketch: ESP8266WebServer/examples/WebUpdate/WebUpdate.ino

On initial upload of a simple sketch that prints hello world, the OTA update fails and the ESP8266 hangs. Cycling the power and uploading the sketch again seems to work. Any ideas why the first attempt always fails? Log below:

Booting Sketch...
Ready! Open http://esp8266-webupdate.local in your browser
Update: ESP8266PCB.cpp.generic.bin
sleep disable
Update Success: 266384
Rebooting...

ets Jan 8 2013,rst cause:1, boot mode:(1,0)

ets Jan 8 2013,rst cause:4, boot mode:(1,0)

wdt reset

cycle power

Booting Sketch...
Ready! Open http://esp8266-webupdate.local in your browser
Update: ESP8266PCB.cpp.generic.bin
sleep disable
Update Success: 266384
Rebooting...

ets Jan 8 2013,rst cause:1, boot mode:(3,0)

load 0x4010f000, len 1264, room 16
tail 0
chksum 0x42
csum 0x42
@cp:0
ld

new sketch starts up OK