Exception on boot

[longmover]

Hi, i can't seem to get this to work using the latest ESPHome running on HA installed on a d1_mini. Compiles and flashes ok but throws an exception on boot. I've tried different GPIO ports but get the same outcome, an i doing something wrong?

Logs and config:

ets Jan 8 2013,rst cause:2, boot mode:(3,6)

load 0x4010f000, len 3460, room 16
tail 4
chksum 0xcc
load 0x3fff20b8, len 40, room 4
tail 4
chksum 0xc9
csum 0xc9
v00068ac0
~ld
[I][logger:214]: Log initialized
[C][ota:461]: There have been 8 suspected unsuccessful boot attempts.
[W][app:022]: Component already registered! (0x3fff1444)
[I][app:029]: Running through setup()...
[C][uart.arduino_esp8266:059]: Setting up UART bus...
[C][wifi:037]: Setting up WiFi...
[D][wifi:373]: Starting scan...

--------------- CUT HERE FOR EXCEPTION DECODER ---------------

Soft WDT reset

stack>>>

ctx: cont
sp: 3ffffc10 end: 3fffffc0 offset: 01a0
3ffffdb0: 3fff0b7c 3fff179c 3fff1444 40210d52
3ffffdc0: 3fff0b7c 3fff179c 3fff1444 40210db5
3ffffdd0: 3fff0b7c 3fff179c 3ffef574 402237f6
3ffffde0: 3fff0b7c 3fff179c 3ffef574 402108c4
3ffffdf0: 3fff1024 3fff179c 00000002 402102c9
3ffffe00: 0000006e 3fff1444 3ffe85dc 00000000
3ffffe10: 3fff103c 3fff1050 3fff1024 3fff1024
3ffffe20: 0000006e 00000020 3fff17c4 0000ea60
3ffffe30: fffec533 0000000a 3ffef574 4022f300
3ffffe40: 00000000 3ffffe60 0000000b 00000100
3ffffe50: 3fff0b7c 0000000a 3ffef574 4020f691
3ffffe60: 0000000b 0000000b 3fff18c4 40210ee8
3ffffe70: 0000002c 3fff18c4 00000000 00000000
3ffffe80: 00000000 00000000 3fff135c 3ffef618
3ffffe90: 000000bc 3ffef574 00000000 4021185a
3ffffea0: 3fff0d9c 0000001b 0000001e 00000000
3ffffeb0: 00000000 00000000 00000000 00000000
3ffffec0: 3ffffec8 0000000c 31437865 67445a6c
3ffffed0: 4c557846 00000000 00000000 00000000
3ffffee0: 00000000 00000000 00000000 00000000
3ffffef0: 00000000 00000000 3fffff00 00000005 <
3fffff00: 62697270 00000065 00000000 00000000
3fffff10: 00000000 00000000 3fff0cf4 00000012
3fffff20: 0000001e 00000000 00000000 00000000
3fffff30: 00000000 00000000 00000000 00000000
3fffff40: 00000000 00000000 00000000 00000000
3fffff50: 3fffff58 00000003 40223978 40210a6c
3fffff60: 4c550066 feefef00 3fff0d94 3fff0d98
3fffff70: 3fff0d98 feefeffe feefeffe feefeffe
3fffff80: 3fff135c feefeffe feefeffe feefeffe
3fffff90: feefeffe feefeffe feefeffe 3ffef95c
3fffffa0: 3fffdad0 00000000 3ffef948 4021fef4
3fffffb0: feefeffe feefeffe 3ffe85d8 40100701
<<<stack<<<

--------------- CUT HERE FOR EXCEPTION DECODER ---------------

Config:
esphome:
name: esp-boiler
includes:
- vaillantx6.h

esp8266:
board: d1_mini

#web server
web_server:

Enable logging

logger:

Enable Home Assistant API

api:

ota:
password: [redacted]

wifi:
ssid: !secret wifi_ssid
password: !secret wifi_password

Enable fallback hotspot (captive portal) in case wifi connection fails

ap:
ssid: "Esp-Boiler Fallback Hotspot"
password: [redacted]

uart:
id: uart_bus
tx_pin: GPIO2
rx_pin: GPIO15
baud_rate: 9600

sensor:

• platform: template
  id: vaill1
  name: "vl_soll"
  unit_of_measurement: "°C"
  lambda: "return {};"
• name: vl_ist
  id: vaill2
  platform: template
  unit_of_measurement: "°C"
  lambda: "return {};"
• name: vl_set
  id: vaill3
  platform: template
  unit_of_measurement: "°C"
  lambda: "return {};"
• name: ruecklauf
  id: vaill4
  unit_of_measurement: "°C"
  platform: template
  lambda: "return {};"

custom_component:

• lambda: |-
  auto my_x61 = new Vaillantx6(id(uart_bus),id(vaill1),id(vaill2),id(vaill3),id(vaill4));
  App.register_component(my_x61);
  return {my_x61};
  captive_portal:

[longmover]

Some progress, by adding yield() to the end of each while loop it stops the WDT reset but it now halts after
[wifi:373]: Starting scan...

with no further output from the serial console, any help is much appreciated

[longmover]

It's now working, with the following:

int getParm(byte *cmd, int lcmd) {
int val;
write_array(cmd,lcmd);
delay(1000);
while(available()<4){yield();}
if (available()>=4) {
int len = read();
int flag = read();
val = read()*16 + (read()>>4);
} else val=0;
// überflüssige bytes abräumen
while(available()) {
int b = read();
yield();
}
yield();
return val;
}