diff --git a/rtl837x_common.h b/rtl837x_common.h
index 98202b8..5432343 100644
--- a/rtl837x_common.h
+++ b/rtl837x_common.h
@@ -149,7 +149,7 @@ void sleep(uint16_t t);
 void write_char_no_syslog(char c);
 void write_char(char c);
 void print_reg(uint16_t reg);
-uint8_t sfp_read_reg(uint8_t slot, uint8_t reg);
+uint8_t sfp_read_reg(uint8_t slot, uint8_t reg) __banked;
 extern __xdata uint8_t sfp_i2c_fail;
 void reg_bit_set(uint16_t reg_addr, char bit);
 void reg_bit_clear(uint16_t reg_addr, char bit);
diff --git a/rtl837x_pins.c b/rtl837x_pins.c
index 90015b7..ac0cea3 100644
--- a/rtl837x_pins.c
+++ b/rtl837x_pins.c
@@ -1,6 +1,11 @@
 #include "rtl837x_pins.h"
 #include "rtl837x_common.h"
+#include "rtl837x_sfr.h"
 #include "rtl837x_regs.h"
+#include "machine.h"
+
+extern __code const struct machine machine;
+extern __xdata uint8_t sfr_data[4];
 
 #pragma codeseg BANK2
 #pragma constseg BANK2
@@ -121,3 +126,42 @@ void gpio_output_setup(uint8_t pin, __xdata uint8_t initial_val) __banked{
 
 	reg_bit_set(gpio_direction_reg(pin), (pin % 32));
 }
+
+
+/*
+ * Read a register of the EEPROM via I2C
+ */
+uint8_t sfp_read_reg(uint8_t slot, uint8_t reg) __banked
+{
+	if (reg & 0x80) {	// Configure SFP readings address (0x51) as I2C device address
+		reg &= 0x7f;
+		REG_WRITE(RTL837X_REG_I2C_CTRL, 0x00, 0x1 << (I2C_MEM_ADDR_WIDTH-16) | 0,  0x51 >> 5, (0x51 << 3) & 0xff);
+	} else {
+		REG_WRITE(RTL837X_REG_I2C_CTRL, 0x00, 0x1 << (I2C_MEM_ADDR_WIDTH-16) | 0,  0x50 >> 5, (0x50 << 3) & 0xff);
+	}
+
+	reg_read_m(RTL837X_REG_I2C_CTRL);
+	sfr_mask_data(1, 0xfc, i2c_bus_from_scl_pin(machine.sfp_port[slot].i2c.scl) << 5 | i2c_bus_from_sda_pin(machine.sfp_port[slot].i2c.sda) << 2);
+	reg_write_m(RTL837X_REG_I2C_CTRL);
+
+	REG_WRITE(RTL837X_REG_I2C_IN, 0, 0, 0, reg);
+
+	// Execute I2C Read
+	reg_bit_set(RTL837X_REG_I2C_CTRL, 0);
+
+	// Wait for execution to finish
+	do {
+		reg_read_m(RTL837X_REG_I2C_CTRL);
+	} while (sfr_data[3] & 0x1);
+
+	/* Bit 1 is the controller's own failure indication, which the vendor SDK
+	 * looks at and this did not. Without it an unacknowledged address comes
+	 * back as an ordinary byte and the caller cannot tell it from data. */
+	if (sfr_data[3] & 0x2) {
+		sfp_i2c_fail = 1;
+		return 0xff;
+	}
+
+	reg_read_m(RTL837X_REG_I2C_OUT);
+	return sfr_data[3];
+}
diff --git a/rtlplayground.c b/rtlplayground.c
index f8cd721..6926ae5 100644
--- a/rtlplayground.c
+++ b/rtlplayground.c
@@ -1036,45 +1036,6 @@ void sds_config(uint8_t sds, uint8_t mode)
 }
 
 
-/*
- * Read a register of the EEPROM via I2C
- */
-uint8_t sfp_read_reg(uint8_t slot, uint8_t reg)
-{
-	if (reg & 0x80) {	// Configure SFP readings address (0x51) as I2C device address
-		reg &= 0x7f;
-		REG_WRITE(RTL837X_REG_I2C_CTRL, 0x00, 0x1 << (I2C_MEM_ADDR_WIDTH-16) | 0,  0x51 >> 5, (0x51 << 3) & 0xff);
-	} else {
-		REG_WRITE(RTL837X_REG_I2C_CTRL, 0x00, 0x1 << (I2C_MEM_ADDR_WIDTH-16) | 0,  0x50 >> 5, (0x50 << 3) & 0xff);
-	}
-
-	reg_read_m(RTL837X_REG_I2C_CTRL);
-	sfr_mask_data(1, 0xfc, i2c_bus_from_scl_pin(machine.sfp_port[slot].i2c.scl) << 5 | i2c_bus_from_sda_pin(machine.sfp_port[slot].i2c.sda) << 2);
-	reg_write_m(RTL837X_REG_I2C_CTRL);
-
-	REG_WRITE(RTL837X_REG_I2C_IN, 0, 0, 0, reg);
-
-	// Execute I2C Read
-	reg_bit_set(RTL837X_REG_I2C_CTRL, 0);
-
-	// Wait for execution to finish
-	do {
-		reg_read_m(RTL837X_REG_I2C_CTRL);
-	} while (sfr_data[3] & 0x1);
-
-	/* Bit 1 is the controller's own failure indication, which the vendor SDK
-	 * looks at and this did not. Without it an unacknowledged address comes
-	 * back as an ordinary byte and the caller cannot tell it from data. */
-	if (sfr_data[3] & 0x2) {
-		sfp_i2c_fail = 1;
-		return 0xff;
-	}
-
-	reg_read_m(RTL837X_REG_I2C_OUT);
-	return sfr_data[3];
-}
-
-
 /*
  * Adds TX Header to uip_buf and calls nic_tx_packet to send the packet
  * over the wire