diff --git a/src/ec/system76/ec/system76_ec.c b/src/ec/system76/ec/system76_ec.c
index 238e630971..ddcb602d4c 100644
--- a/src/ec/system76/ec/system76_ec.c
+++ b/src/ec/system76/ec/system76_ec.c
@@ -4,7 +4,22 @@
 #include <console/system76_ec.h>
 #include <timer.h>
 
+// This is the command region for System76 EC firmware. It must be
+// enabled for LPC in the mainboard.
 #define SYSTEM76_EC_BASE 0x0E00
+#define SYSTEM76_EC_SIZE 256
+
+#define REG_CMD 0
+#define REG_RESULT 1
+
+// When command register is 0, command is complete
+#define CMD_FINISHED 0
+
+// Print command. Registers are unique for each command
+#define CMD_PRINT 4
+#define CMD_PRINT_REG_FLAGS 2
+#define CMD_PRINT_REG_LEN 3
+#define CMD_PRINT_REG_DATA 4
 
 static inline uint8_t system76_ec_read(uint8_t addr)
 {
@@ -19,32 +34,28 @@ static inline void system76_ec_write(uint8_t addr, uint8_t data)
 void system76_ec_init(void)
 {
 	// Clear entire command region
-	for (int i = 0; i < 256; i++)
+	for (int i = 0; i < SYSTEM76_EC_SIZE; i++)
 		system76_ec_write((uint8_t)i, 0);
 }
 
 void system76_ec_flush(void)
 {
-	// Send command
-	system76_ec_write(0, 4);
+	system76_ec_write(REG_CMD, CMD_PRINT);
 
-	// Wait for command completion, for up to 10 milliseconds
-	wait_us(10000, system76_ec_read(0) == 0);
+	// Wait for command completion, for up to 10 milliseconds, with a
+	// test period of 1 microsecond
+	wait_us(10000, system76_ec_read(REG_CMD) == CMD_FINISHED);
 
-	// Clear length
-	system76_ec_write(3, 0);
+	system76_ec_write(CMD_PRINT_REG_LEN, 0);
 }
 
 void system76_ec_print(uint8_t byte)
 {
-	// Read length
-	uint8_t len = system76_ec_read(3);
-	// Write data at offset
-	system76_ec_write(len + 4, byte);
-	// Update length
-	system76_ec_write(3, len + 1);
+	uint8_t len = system76_ec_read(CMD_PRINT_REG_LEN);
+	system76_ec_write(CMD_PRINT_REG_DATA + len, byte);
+	system76_ec_write(CMD_PRINT_REG_LEN, len + 1);
 
 	// If we hit the end of the buffer, or were given a newline, flush
-	if (byte == '\n' || len >= 128)
+	if (byte == '\n' || len >= (SYSTEM76_EC_SIZE - CMD_PRINT_REG_DATA))
 		system76_ec_flush();
 }