Sparkfun ESP32 Thing

Hi,
I flashed a SparkFun ESP32 Thing with Espruino (specifically espruino_1v99_esp32.bin) however I just get junk out of it.

If I reset I see the bootloader (I assume) print some stuff then I get junk eg..

[Maelstrom 16:47] ~ >cu -l /dev/cu.usbserial-DN02MPA4 -s 115200
Connected.
ets Jun  8 2016 00:22:57

rst:0x1 (POWERON_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
ets Jun  8 2016 00:22:57

rst:0x10 (RTCWDT_RTC_RESET),boot:0x13 (SPI_FAST_FLASH_BOOT)
configsip: 0, SPIWP:0xee
clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
mode:DIO, clock div:2
load:0x3fff0018,len:4
load:0x3fff001c,len:2364
load:0x40078000,len:0
load:0x40078000,len:10880
entry 0x40078c4c
���1Il���

I tried a few different baud rates (9600, 19200, 38400, 57600, 115200, 230400, 921600) and none of them produced anything sensible except for the boot loader at 115200.

Any help appreciated, thanks.

BTW I flashed this board with MicroPython and it worked so I think the board is OK.