diff --git a/firmware/lib/hardware_mapping/ec_pins.h b/firmware/lib/hardware_mapping/ec_pins.h
index 7b23ae7..9eb8cc9 100644
--- a/firmware/lib/hardware_mapping/ec_pins.h
+++ b/firmware/lib/hardware_mapping/ec_pins.h
@@ -15,8 +15,8 @@
 
 // RS485 Busses (UART6 and UART2)
 // these are declared in ec_main
-extern HardwareSerial RS485_6; // RS485 on UART 6
-extern HardwareSerial RS485_2; // RS485 on UART 2
+extern Uart RS485_6; // RS485 on UART 6
+extern Uart RS485_2; // RS485 on UART 2
 
 #define PIN_RS485_6_RX PG9
 #define PIN_RS485_6_TX PG14
diff --git a/firmware/lib/serial_comms/CommsSerial.h b/firmware/lib/serial_comms/CommsSerial.h
index 7f05e6e..d7d9f65 100644
--- a/firmware/lib/serial_comms/CommsSerial.h
+++ b/firmware/lib/serial_comms/CommsSerial.h
@@ -68,7 +68,7 @@ template <typename BaseSerial> class CommsSerial_t : public BaseSerial {
   }
 };
 
-extern CommsSerial_t<HardwareSerial> HW_CommsSerial;
+extern CommsSerial_t<Uart> HW_CommsSerial;
 extern CommsSerial_t<USBSerial> USB_CommsSerial;
 
 #define CommsSerial HW_CommsSerial
\ No newline at end of file
diff --git a/firmware/lib/throttle_valves/AMT242AV.cpp b/firmware/lib/throttle_valves/AMT242AV.cpp
index 8acb538..79b7537 100644
--- a/firmware/lib/throttle_valves/AMT242AV.cpp
+++ b/firmware/lib/throttle_valves/AMT242AV.cpp
@@ -5,7 +5,7 @@
 // max reading for a 12 bit encoder
 #define MAX_READING ((1 << 12) - 1)
 
-AMT242AV::AMT242AV(HardwareSerial &uart, unsigned int SEL, uint8_t ID) : uart(uart), SEL(SEL), ID(ID) {}
+AMT242AV::AMT242AV(Uart &uart, unsigned int SEL, uint8_t ID) : uart(uart), SEL(SEL), ID(ID) {}
 
 void AMT242AV::begin() {
   digitalWrite(SEL, LOW);
diff --git a/firmware/lib/throttle_valves/AMT242AV.h b/firmware/lib/throttle_valves/AMT242AV.h
index ba0175b..cfce3d9 100644
--- a/firmware/lib/throttle_valves/AMT242AV.h
+++ b/firmware/lib/throttle_valves/AMT242AV.h
@@ -6,7 +6,7 @@
 // encoder)
 class AMT242AV {
 public:
-  AMT242AV(HardwareSerial &uart, unsigned int SEL, uint8_t ID);
+  AMT242AV(Uart &uart, unsigned int SEL, uint8_t ID);
   void begin();
 
   bool read_pos(float *out, int max_retries = 10);
@@ -14,7 +14,7 @@ class AMT242AV {
   void reset();
 
 private:
-  HardwareSerial &uart;
+  Uart &uart;
   unsigned int SEL;
   uint8_t ID;
 
diff --git a/firmware/lib/throttle_valves/ThrottleValves.h b/firmware/lib/throttle_valves/ThrottleValves.h
index 27a82e6..c47b28f 100644
--- a/firmware/lib/throttle_valves/ThrottleValves.h
+++ b/firmware/lib/throttle_valves/ThrottleValves.h
@@ -5,7 +5,7 @@
 
 class ThrottleValve {
 public:
-  ThrottleValve(uint16_t motor_can_id, HardwareSerial &enc_uart, unsigned int enc_SEL, unsigned int enc_ID)
+  ThrottleValve(uint16_t motor_can_id, Uart &enc_uart, unsigned int enc_SEL, unsigned int enc_ID)
       : motor(motor_can_id), encoder(enc_uart, enc_SEL, enc_ID) {};
 
   void begin();
diff --git a/firmware/platformio.ini b/firmware/platformio.ini
index 00fbaef..a481298 100644
--- a/firmware/platformio.ini
+++ b/firmware/platformio.ini
@@ -9,7 +9,7 @@
 ; https://docs.platformio.org/page/projectconf.html
 
 [env]
-platform = ststm32 @ 19.6.0
+platform = ststm32 @ 20.0.0
 framework = arduino
 
 monitor_speed = 57600
diff --git a/firmware/src/ec_main.cpp b/firmware/src/ec_main.cpp
index 55d3af5..ed80c3a 100644
--- a/firmware/src/ec_main.cpp
+++ b/firmware/src/ec_main.cpp
@@ -12,11 +12,11 @@
 
 // shared interfaces
 CommsSerial_t<USBSerial> USB_CommsSerial;
-CommsSerial_t<HardwareSerial> HW_CommsSerial(PIN_HW_COMM_SERIAL_RX, PIN_HW_COMM_SERIAL_TX);
-CommsSerial_t<HardwareSerial> HW_FallbackSerial(PIN_HW_FALLBACK_SERIAL_RX, PIN_HW_FALLBACK_SERIAL_TX);
+CommsSerial_t<Uart> HW_CommsSerial(PIN_HW_COMM_SERIAL_RX, PIN_HW_COMM_SERIAL_TX);
+CommsSerial_t<Uart> HW_FallbackSerial(PIN_HW_FALLBACK_SERIAL_RX, PIN_HW_FALLBACK_SERIAL_TX);
 // TODO - configure DE pin
-HardwareSerial RS485_6(PIN_RS485_6_RX, PIN_RS485_6_TX, PIN_RS485_6_DE);
-HardwareSerial RS485_2(PIN_RS485_2_RX, PIN_RS485_2_TX, PIN_RS485_2_DE);
+Uart RS485_6(PIN_RS485_6_RX, PIN_RS485_6_TX, PIN_RS485_6_DE);
+Uart RS485_2(PIN_RS485_2_RX, PIN_RS485_2_TX, PIN_RS485_2_DE);
 
 SPIClass PT_TC_SPI_1(PIN_PT_TC_SPI_1_MOSI, PIN_PT_TC_SPI_1_MISO, PIN_PT_TC_SPI_1_SCK);
 SPIClass PT_TC_SPI_3(PIN_PT_TC_SPI_3_MOSI, PIN_PT_TC_SPI_3_MISO, PIN_PT_TC_SPI_3_SCK);
diff --git a/firmware/src/fc_main.cpp b/firmware/src/fc_main.cpp
index 8b26fa9..c8086ba 100644
--- a/firmware/src/fc_main.cpp
+++ b/firmware/src/fc_main.cpp
@@ -1,6 +1,11 @@
-#include "CommsSerial.h"
+// #include "CommsSerial.h"
 #include <Arduino.h>
 
-void setup() {}
+void setup() 
+{
+    Serial.begin(9600);
+
+    Serial.println("init"); // had to add this; for some reason without it we don't pull in Print.cpp which causes a linker error because _write is not defined
+}
 
 void loop() {}
\ No newline at end of file
diff --git a/firmware/src/prog_main.cpp b/firmware/src/prog_main.cpp
index 75716b7..f79b300 100644
--- a/firmware/src/prog_main.cpp
+++ b/firmware/src/prog_main.cpp
@@ -8,8 +8,8 @@
 // Citations commented as [pg#]
 
 CommsSerial_t<USBSerial> USB_CommsSerial;
-CommsSerial_t<HardwareSerial> HW_CommsSerial(PIN_HW_COMM_SERIAL_RX, PIN_HW_COMM_SERIAL_TX);
-CommsSerial_t<HardwareSerial> HW_FallbackSerial(PIN_HW_FALLBACK_SERIAL_RX, PIN_HW_FALLBACK_SERIAL_TX);
+CommsSerial_t<Uart> HW_CommsSerial(PIN_HW_COMM_SERIAL_RX, PIN_HW_COMM_SERIAL_TX);
+CommsSerial_t<Uart> HW_FallbackSerial(PIN_HW_FALLBACK_SERIAL_RX, PIN_HW_FALLBACK_SERIAL_TX);
 
 SPIClass Prog_SPI(PIN_PROG_SPI_MOSI, PIN_PROG_SPI_MISO, PIN_PROG_SPI_SCK);