diff --git a/code/espurna/pwm.c b/code/espurna/pwm.c
index b05df7dc..ff6111ba 100644
--- a/code/espurna/pwm.c
+++ b/code/espurna/pwm.c
@@ -122,7 +122,7 @@ pwm_intr_handler(void)
 
 	do {
 		// force write to GPIO registers on each loop
-		asm volatile ("" : : : "memory");
+		__asm__ volatile ("" : : : "memory");
 
 		gpio->out_w1ts = (uint32_t)(pwm_state.current_set[pwm_state.current_phase].on_mask);
 		gpio->out_w1tc = (uint32_t)(pwm_state.current_set[pwm_state.current_phase].off_mask);
@@ -144,7 +144,7 @@ pwm_intr_handler(void)
 			do {
 				ticks -= 1;
 				// stop compiler from optimizing delay loop to noop
-				asm volatile ("" : : : "memory");
+				__asm__ volatile ("" : : : "memory");
 			} while (ticks > 0);
 		}
 
diff --git a/code/platformio.ini b/code/platformio.ini
index 3ed747d1..063cb92b 100644
--- a/code/platformio.ini
+++ b/code/platformio.ini
@@ -32,10 +32,10 @@ extra_configs =
 #   arduino core 2.6.1 = platformIO 2.3.0 (not supported)
 #   arduino core 2.6.2 = platformIO 2.3.1 (not supported)
 #   arduino core 2.6.3 = platformIO 2.4.0
-#   arduino core 2.7.1 = platformIO 2.5.1
+#   arduino core 2.7.1 = platformIO 2.5.3
 # ------------------------------------------------------------------------------
 platform_2_3_0 = espressif8266@1.5.0
-platform_latest = espressif8266@2.5.1
+platform_latest = espressif8266@2.5.3
 
 # ------------------------------------------------------------------------------
 # FLASH SIZE:
@@ -118,28 +118,19 @@ debug_flags =
 
 shared_libdeps_dir = libraries/
 
-# ------------------------------------------------------------------------------
-# COMMON ENVIRONMENT SETTINGS:
-# ------------------------------------------------------------------------------
-[env]
-platform = ${common.platform_2_3_0}
-framework = arduino
-board_build.flash_mode = dout
-build_flags = ${common.build_flags}
-monitor_speed = 115200
-upload_speed = 115200
-extra_scripts = pre:scripts/pio_pre.py, scripts/pio_main.py
-lib_extra_dirs =
-    ${common.shared_libdeps_dir}
+# TODO: right now we depend on external toolchain url b/c toolchain version is hard-coded into the platform
+git_platform_packages =
+    framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git
+    toolchain-xtensa @ https://github.com/earlephilhower/esp-quick-toolchain/releases/download/3.0.0-gnu12/x86_64-linux-gnu.xtensa-lx106-elf-0474ae9.200706.tar.gz
+
+# XXX: 2.3.0 depends on these
+legacy_lib_deps =
+    https://github.com/xoseperez/Time
+    https://github.com/xoseperez/NtpClient.git#0942ebc
 
-# ------------------------------------------------------------------------------
-# LIBRARIES: required dependencies
-#   Please note that we don't always use the latest version of a library.
-# ------------------------------------------------------------------------------
 lib_deps =
     ArduinoJson@5.13.4
     https://github.com/marvinroger/async-mqtt-client#v0.8.1
-    Brzo I2C
     https://github.com/xoseperez/eeprom_rotate#0.9.2
     https://github.com/plerup/espsoftwareserial#3.4.1
     https://github.com/me-no-dev/ESPAsyncTCP#7e9ed22
@@ -152,22 +143,45 @@ lib_deps =
     https://github.com/xoseperez/my92xx#3.0.1
     https://github.com/256dpi/arduino-mqtt#196556b6
     https://bitbucket.org/xoseperez/nofuss.git#0.3.0
-    https://github.com/xoseperez/NtpClient.git#0942ebc
     OneWire
     PZEM004T
     PubSubClient
     rc-switch
     https://github.com/LowPowerLab/RFM69#7008d57a
     https://github.com/xoseperez/rpnlib.git#0.3.0
-    https://github.com/xoseperez/Time
     NewPing
     https://github.com/sparkfun/SparkFun_VEML6075_Arduino_Library#V_1.0.3
     https://github.com/pololu/vl53l1x-arduino#1.0.1
     https://github.com/mcleng/MAX6675-Library#2.0.1
     https://github.com/ThingPulse/esp8266-oled-ssd1306#3398c97
     Adafruit SI1145 Library@~1.1.1
+
+# ------------------------------------------------------------------------------
+# COMMON ENVIRONMENT SETTINGS:
+# ------------------------------------------------------------------------------
+[env]
+platform = ${common.platform_2_3_0}
+framework = arduino
+board_build.flash_mode = dout
+build_flags = ${common.build_flags}
+monitor_speed = 115200
+upload_speed = 115200
+extra_scripts = pre:scripts/pio_pre.py, scripts/pio_main.py
+lib_extra_dirs =
+    ${common.shared_libdeps_dir}
+
+# ------------------------------------------------------------------------------
+# LIBRARIES: required dependencies
+#   Please note that we don't always use the latest version of a library.
+# ------------------------------------------------------------------------------
+lib_deps =
+    ${common.lib_deps}
+
 lib_ignore =
     AsyncTCP
+    Brzo I2C
+    Time
+    NtpClientLib
 
 # ------------------------------------------------------------------------------
 # Base enrivonments, -DMANUFACTURER=..., -DDEVICE=... must be set:
@@ -179,18 +193,38 @@ lib_ignore =
 [env:esp8266-512k-base]
 board = ${common.board_512k}
 board_build.ldscript = ${common.ldscript_512k}
+lib_deps =
+    ${common.legacy_lib_deps}
+    ${common.lib_deps}
+lib_ignore =
+    AsyncTCP
 
 [env:esp8266-1m-base]
 board = ${common.board_1m}
 board_build.ldscript = ${common.ldscript_1m}
+lib_deps =
+    ${common.legacy_lib_deps}
+    ${common.lib_deps}
+lib_ignore =
+    AsyncTCP
 
 [env:esp8266-2m-base]
 board = ${common.board_2m}
 board_build.ldscript = ${common.ldscript_2m}
+lib_deps =
+    ${common.legacy_lib_deps}
+    ${common.lib_deps}
+lib_ignore =
+    AsyncTCP
 
 [env:esp8266-4m-base]
 board = ${common.board_4m}
 board_build.ldscript = ${common.ldscript_4m}
+lib_deps =
+    ${common.legacy_lib_deps}
+    ${common.lib_deps}
+lib_ignore =
+    AsyncTCP
 
 [env:esp8266-1m-latest-base]
 platform = ${common.platform_latest}
@@ -211,21 +245,21 @@ board_build.ldscript = ${common.ldscript_4m}
 platform = ${common.platform_latest}
 board = ${common.board_1m}
 platform_packages =
-    framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git
+    ${common.git_platform_packages}
 board_build.ldscript = ${common.ldscript_1m}
 
 [env:esp8266-2m-git-base]
 platform = ${common.platform_latest}
 board = ${common.board_2m}
 platform_packages =
-    framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git
+    ${common.git_platform_packages} 
 board_build.ldscript = ${common.ldscript_2m}
 
 [env:esp8266-4m-git-base]
 platform = ${common.platform_latest}
 board = ${common.board_4m}
 platform_packages =
-    framework-arduinoespressif8266 @ https://github.com/esp8266/Arduino.git
+    ${common.git_platform_packages}
 board_build.ldscript = ${common.ldscript_4m}
 
 # ------------------------------------------------------------------------------