OTA update mdash new build_vars not working

General
1

I am trying to Ota update but new build_vars are not taking effect through mdash
Working fine when trying to update through (mos flash).
Initial firmware mos.yml file contains
MOS.YML

build_vars:
  MGOS_WIFI_ENABLE_AP_STA: 1

Init.js

load('api_timer.js');
load('api_dht.js');
load('api_http.js');
load('api_gpio.js');
load('api_config.js');
load('api_sys.js');
load('api_rpc.js');
load('api_ota.js');
let dht = DHT.create(0, DHT.DHT11);
RPC.addHandler('GetTemp', function() {
  return {Temp:dht.getTemp(),Humidity:dht.getHumidity()};
});
//===================================================================

NEW Firmware files for update through ota
MOS.YML

build_vars:
  MGOS_WIFI_ENABLE_AP_STA: 1
  MGOS_ADC_MODE_VDD: 1
libs(added only)
  - origin: https://github.com/mongoose-os-libs/adc

Init.js

load('api_timer.js');
load('api_dht.js');
load('api_http.js');
load('api_gpio.js');
load('api_config.js');
load('api_sys.js');
load('api_rpc.js');
load('api_ota.js');
load('api_adc.js');
ADC.enable(0);
let dht = DHT.create(0, DHT.DHT11);
RPC.addHandler('GetTemp', function() {
  return {Temp:dht.getTemp(),Humidity:dht.getHumidity(),Battery:ADC.read(0)};

});

Battery:ADC.read(0) always return 65535 but working fine if updated through usb (mos flash)

2

Setting MGOS_ADC_MODE_VDD to 1 will modify esp_init_data_default.bin and it’s only updated by mos flash.
AFAIK, OTA update can only update the application and the filesystem.