void setup() {
  M5.begin(true,true,true,true);
  M5.Power.begin();
  WiFi.begin(ssid, password);
  M5.Lcd.println("TODO");
  delay(500);
}

void loop() {
  M5.update();
  delay(1000);
}

Doesn't work on my old Core:

18:35:52.956 -> rst:0x1 (POWERON_RESET),boot:0x17 (SPI_FAST_FLASH_BOOT)
18:35:52.956 -> configsip: 0, SPIWP:0xee
18:35:52.956 -> clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
18:35:52.956 -> mode:DIO, clock div:1
18:35:52.956 -> load:0x3fff0018,len:4
18:35:52.956 -> load:0x3fff001c,len:1216
18:35:52.956 -> ho 0 tail 12 room 4
18:35:52.956 -> load:0x40078000,len:10944
18:35:52.956 -> load:0x40080400,len:6388
18:35:52.956 -> entry 0x400806b4
18:35:53.287 -> M5Stack initializing...OK
18:35:53.751 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 0 - WIFI_READY
18:35:53.751 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 2 - STA_START
18:35:57.790 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 5 - STA_DISCONNECTED
18:35:57.790 -> [W][WiFiGeneric.cpp:391] _eventCallback(): Reason: 2 - AUTH_EXPIRE
18:36:01.862 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 5 - STA_DISCONNECTED
18:36:01.862 -> [W][WiFiGeneric.cpp:391] _eventCallback(): Reason: 2 - AUTH_EXPIRE
18:36:05.901 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 5 - STA_DISCONNECTED
18:36:05.901 -> [W][WiFiGeneric.cpp:391] _eventCallback(): Reason: 2 - AUTH_EXPIRE
18:36:09.941 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 5 - STA_DISCONNECTED
18:36:09.941 -> [W][WiFiGeneric.cpp:391] _eventCallback(): Reason: 2 - AUTH_EXPIRE
18:36:14.014 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 5 - STA_DISCONNECTED
18:36:14.014 -> [W][WiFiGeneric.cpp:391] _eventCallback(): Reason: 2 - AUTH_EXPIRE
18:36:18.053 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 5 - STA_DISCONNECTED
18:36:18.053 -> [W][WiFiGeneric.cpp:391] _eventCallback(): Reason: 2 - AUTH_EXPIRE
18:36:22.091 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 5 - STA_DISCONNECTED
18:36:22.091 -> [W][WiFiGeneric.cpp:391] _eventCallback(): Reason: 2 - AUTH_EXPIRE

It works on Fire:

18:40:11.811 -> rst:0x1 (POWERON_RESET),boot:0x17 (SPI_FAST_FLASH_BOOT)
18:40:11.811 -> configsip: 0, SPIWP:0xee
18:40:11.811 -> clk_drv:0x00,q_drv:0x00,d_drv:0x00,cs0_drv:0x00,hd_drv:0x00,wp_drv:0x00
18:40:11.811 -> mode:DIO, clock div:1
18:40:11.811 -> load:0x3fff0018,len:4
18:40:11.811 -> load:0x3fff001c,len:1216
18:40:11.811 -> ho 0 tail 12 room 4
18:40:11.811 -> load:0x40078000,len:10944
18:40:11.811 -> load:0x40080400,len:6388
18:40:11.811 -> entry 0x400806b4
18:40:12.142 -> M5Stack initializing...[W][sd_diskio.cpp:169] sdCommand(): no token received
18:40:12.241 -> [W][sd_diskio.cpp:169] sdCommand(): no token received
18:40:12.341 -> [W][sd_diskio.cpp:169] sdCommand(): no token received
18:40:12.473 -> [E][sd_diskio.cpp:194] sdCommand(): Card Failed! cmd: 0x00
18:40:12.473 -> [W][sd_diskio.cpp:505] ff_sd_initialize(): GO_IDLE_STATE failed
18:40:12.473 -> [E][sd_diskio.cpp:775] sdcard_mount(): f_mount failed: (3) The physical drive cannot work
18:40:12.473 -> [W][sd_diskio.cpp:169] sdCommand(): no token received
18:40:12.539 -> [W][sd_diskio.cpp:169] sdCommand(): no token received
18:40:12.638 -> [W][sd_diskio.cpp:169] sdCommand(): no token received
18:40:12.738 -> [E][sd_diskio.cpp:194] sdCommand(): Card Failed! cmd: 0x00
18:40:13.069 -> OK
18:40:13.201 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 0 - WIFI_READY
18:40:13.201 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 2 - STA_START
18:40:15.353 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 4 - STA_CONNECTED
18:40:15.386 -> [D][WiFiGeneric.cpp:374] _eventCallback(): Event: 7 - STA_GOT_IP
18:40:15.386 -> [D][WiFiGeneric.cpp:419] _eventCallback(): STA IP: 192.168.1.161, MASK: 255.255.255.0, GW: 192.168.1.254

Any clue?