diff --git a/Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.cpp b/Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.cpp
index a5a3c2bdfb..d47b960ab5 100644
--- a/Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.cpp
+++ b/Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.cpp
@@ -55,6 +55,7 @@
 // --------------------------------------------------------------------------
 // Public Variables
 // --------------------------------------------------------------------------
+USBSerial SerialUSB;
 
 uint16_t HAL_adc_result;
 
diff --git a/Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.h b/Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.h
index 23b8be33a7..fdbb5a53c0 100644
--- a/Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.h
+++ b/Marlin/src/HAL/HAL_STM32F1/HAL_Stm32f1.h
@@ -69,6 +69,7 @@
   #error "SERIAL_PORT must be from -1 to 3"
 #endif
 #if SERIAL_PORT == -1
+extern USBSerial SerialUSB;
   #define MYSERIAL0 SerialUSB
 #elif SERIAL_PORT == 0
   #define MYSERIAL0 Serial
@@ -88,6 +89,7 @@
   #endif
   #define NUM_SERIAL 2
   #if SERIAL_PORT_2 == -1
+  extern USBSerial SerialUSB;
     #define MYSERIAL1 SerialUSB
   #elif SERIAL_PORT_2 == 0
     #define MYSERIAL1 Serial
diff --git a/Marlin/src/HAL/HAL_STM32F1/HAL_spi_Stm32f1.cpp b/Marlin/src/HAL/HAL_STM32F1/HAL_spi_Stm32f1.cpp
index 7406c2d782..aed7e2dcef 100644
--- a/Marlin/src/HAL/HAL_STM32F1/HAL_spi_Stm32f1.cpp
+++ b/Marlin/src/HAL/HAL_STM32F1/HAL_spi_Stm32f1.cpp
@@ -41,6 +41,7 @@
 #include "pins_arduino.h"
 #include "spi_pins.h"
 #include "../../core/macros.h"
+#include <spi.h>
 
 // --------------------------------------------------------------------------
 // Public Variables
@@ -166,7 +167,7 @@ void spiSendBlock(uint8_t token, const uint8_t* buf) {
 
 /** Begin SPI transaction, set clock, bit order, data mode */
 void spiBeginTransaction(uint32_t spiClock, uint8_t bitOrder, uint8_t dataMode) {
-  spiConfig = SPISettings(spiClock, bitOrder, dataMode);
+  spiConfig = SPISettings(spiClock, (BitOrder)bitOrder, dataMode);
 
   SPI.beginTransaction(spiConfig);
 }
diff --git a/Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.cpp b/Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.cpp
index 3e890999d6..21b7033671 100644
--- a/Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.cpp
+++ b/Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.cpp
@@ -163,4 +163,51 @@ bool HAL_timer_interrupt_enabled(const uint8_t timer_num) {
   return false;
 }
 
+timer_dev* get_timer_dev(int number) {
+  switch (number) {
+    #if STM32_HAVE_TIMER(1)
+    case 1: return &timer1;
+    #endif
+    #if STM32_HAVE_TIMER(2)
+    case 2: return &timer2;
+    #endif
+    #if STM32_HAVE_TIMER(3)
+    case 3: return &timer3;
+    #endif
+    #if STM32_HAVE_TIMER(4)
+    case 4: return &timer4;
+    #endif
+    #if STM32_HAVE_TIMER(5)
+    case 5: return &timer5;
+    #endif
+    #if STM32_HAVE_TIMER(6)
+    case 6: return &timer6;
+    #endif
+    #if STM32_HAVE_TIMER(7)
+    case 7: return &timer7;
+    #endif
+    #if STM32_HAVE_TIMER(8)
+    case 8: return &timer8;
+    #endif
+    #if STM32_HAVE_TIMER(9)
+    case 9: return &timer9;
+    #endif
+    #if STM32_HAVE_TIMER(10)
+    case 10: return &timer10;
+    #endif
+    #if STM32_HAVE_TIMER(11)
+    case 11: return &timer11;
+    #endif
+    #if STM32_HAVE_TIMER(12)
+    case 12: return &timer12;
+    #endif
+    #if STM32_HAVE_TIMER(13)
+    case 13: return &timer14;
+    #endif
+    #if STM32_HAVE_TIMER(14)
+    case 14: return &timer14;
+    #endif
+    }
+}
+
 #endif // __STM32F1__
diff --git a/Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.h b/Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.h
index 6c2c6a68c8..08486a6ffd 100644
--- a/Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.h
+++ b/Marlin/src/HAL/HAL_STM32F1/HAL_timers_Stm32f1.h
@@ -32,6 +32,7 @@
 // --------------------------------------------------------------------------
 
 #include <stdint.h>
+#include <libmaple/timer.h>
 
 // --------------------------------------------------------------------------
 // Defines
@@ -56,8 +57,9 @@ typedef uint16_t hal_timer_t;
 #define TEMP_TIMER_NUM 2  // index of timer to use for temperature
 #define TEMP_TIMER_CHAN 1 // Channel of the timer to use for compare and interrupts
 
-#define CAT(a, ...) a ## __VA_ARGS__
-#define TIMER_DEV(num) CAT (&timer, num)
+timer_dev* get_timer_dev(int number);
+
+#define TIMER_DEV(num) get_timer_dev(num)
 
 #define STEP_TIMER_DEV TIMER_DEV(STEP_TIMER_NUM)
 #define TEMP_TIMER_DEV TIMER_DEV(TEMP_TIMER_NUM)
@@ -86,7 +88,6 @@ typedef uint16_t hal_timer_t;
 
 #define HAL_timer_get_count(timer_num) timer_get_count(TIMER_DEV(timer_num))
 
-
 #define HAL_ENABLE_ISRs() do { if (thermalManager.in_temp_isr)DISABLE_TEMPERATURE_INTERRUPT(); else ENABLE_TEMPERATURE_INTERRUPT(); ENABLE_STEPPER_DRIVER_INTERRUPT(); } while(0)
 // TODO change this
 
diff --git a/Marlin/src/lcd/malyanlcd.cpp b/Marlin/src/lcd/malyanlcd.cpp
index 14f20859f9..2292abd1b1 100644
--- a/Marlin/src/lcd/malyanlcd.cpp
+++ b/Marlin/src/lcd/malyanlcd.cpp
@@ -393,7 +393,7 @@ void update_usb_status(const bool forceUpdate) {
  * The optimize attribute fixes a register Compile
  * error for amtel.
  */
-void lcd_update() _O2 {
+void lcd_update() {
   static char inbound_buffer[MAX_CURLY_COMMAND];
 
   // First report USB status.