Bug: JSON.parse(undefined) reboots the ESP8266

I flashed the device with "espruino_2v04_esp8266_4mb_combined_4096­.bin".
The first command I typed in after connecting is "JSON.parse(undefined)" (no Wifi/no other devices connected).
The ESP8266 is USB-powered, and this works fine with Wifi and a few Neopixels normally (when not using this code).

>    JSON.parse(undefined)
 ets Jan  8 2013,rst cause:2, boot mode:(3,7)
load 0x40100000, len 2408, room 16
tail 8
chksum 0xe5
load 0x3ffe8000, len 776, room 0
tail 8
chksum 0x84
load 0x3ffe8310, len 632, room 0
tail 8
chksum 0xd8
csum 0xd8
2nd boot version : 1.6
  SPI Speed      : 80MHz
  SPI Mode       : DIO
  SPI Flash Size & Map: 32Mbit(1024KB+1024KB)
jump to run user1 @ 1000
ãänì{ûo|ällld`c<sd'à'ãd`ãrÛl$þ
 ____                 _
|  __|___ ___ ___ _ _|_|___ ___
|  __|_ -| . |  _| | | |   | . |
|____|___|  _|_| |___|_|_|_|___|
         |_| espruino.com
 2v04 (c) 2019 G.Williams
Espruino is Open Source. Our work is supported
only by sales of official boards and donations:
http://espruino.com/Donate
Flash map 4MB:1024/1024, manuf 0xc8 chip 0x4016
>process.memory();
={ free: 1575, usage: 25, total: 1600, history: 0,
  gc: 0, gctime: 1.901 }
>process.env;
={
  VERSION: "2v04",
  GIT_COMMIT: "3956264e",
  BOARD: "ESP8266_4MB",
  FLASH: 0, RAM: 81920,
  SERIAL: "a020a61c-4bc6",
  CONSOLE: "Serial1",
  MODULES: "Flash,Storage,hea" ... "r,crypto,neopixel",
  EXPTR: 1073643636 }
>console.log(process.env.MODULES);
Flash,Storage,heatshrink,net,dgram,http,­NetworkJS,Wifi,ESP8266,TelnetServer,cryp­to,neopixel
=undefined
>require("ESP8266").getState();
={
  sdkVersion: "2.2.1(6ab97e9)",
  cpuFrequency: 160, freeHeap: 15464, maxCon: 10,
  flashMap: "4MB:1024/1024",
  flashKB: 4096,
  flashChip: "0xc8 0x4016"
 }
>require("Flash").getFree();
=[
  { addr: 2097152, length: 1048576 },
  { addr: 3145728, length: 262144 },
  { addr: 3407872, length: 262144 },
  { addr: 3670016, length: 262144 },
  { addr: 3932160, length: 241664 }
 ]
>require("Storage").getFree();
=16
>