diff --git a/src/board/system76/darp5/board.mk b/src/board/system76/darp5/board.mk
index d1dfc77..83dced9 100644
--- a/src/board/system76/darp5/board.mk
+++ b/src/board/system76/darp5/board.mk
@@ -42,3 +42,7 @@ flash: $(BUILD)/ec.rom
 isp: $(BUILD)/ec.rom
 	cargo build --manifest-path ecflash/Cargo.toml --example isp --release
 	sudo ecflash/target/release/examples/isp $<
+
+version:
+	cargo build --manifest-path ecflash/Cargo.toml --example smfi --release
+	sudo ecflash/target/release/examples/smfi
diff --git a/src/board/system76/darp5/include/board/smfi.h b/src/board/system76/darp5/include/board/smfi.h
new file mode 100644
index 0000000..532ef23
--- /dev/null
+++ b/src/board/system76/darp5/include/board/smfi.h
@@ -0,0 +1,7 @@
+#ifndef _BOARD_SMFI_H
+#define _BOARD_SMFI_H
+
+void smfi_init(void);
+void smfi_event(void);
+
+#endif // _BOARD_SMFI_H
diff --git a/src/board/system76/darp5/main.c b/src/board/system76/darp5/main.c
index 8d4643e..91f94eb 100644
--- a/src/board/system76/darp5/main.c
+++ b/src/board/system76/darp5/main.c
@@ -17,6 +17,7 @@
 #include <board/ps2.h>
 #include <board/pwm.h>
 #include <board/smbus.h>
+#include <board/smfi.h>
 #include <common/debug.h>
 #include <common/macro.h>
 #include <common/version.h>
@@ -45,6 +46,7 @@ void init(void) {
     pmc_init();
     pwm_init();
     smbus_init();
+    smfi_init();
 
     //TODO: INTC
 }
@@ -113,7 +115,9 @@ void main(void) {
         }
         // Handles ACPI communication
         pmc_event(&PMC_1);
+        // AP/EC communication over SMFI
+        smfi_event();
         // Idle until next timer interrupt
-        PCON |= 1;
+        //Disabled until interrupts used: PCON |= 1;
     }
 }
diff --git a/src/board/system76/darp5/pnp.c b/src/board/system76/darp5/pnp.c
index 1146a87..6f9ab5b 100644
--- a/src/board/system76/darp5/pnp.c
+++ b/src/board/system76/darp5/pnp.c
@@ -41,6 +41,12 @@ void pnp_enable() {
     pnp_write(0x07, 0x05);
     pnp_write(0x30, 0x01);
 
+    // Enable SMFI
+    pnp_write(0x07, 0x0F);
+    pnp_write(0xF5, 0x00);
+    pnp_write(0xF6, 0x01);
+    pnp_write(0x30, 0x01);
+
     // Enable SWUC
     pnp_write(0x07, 0x04);
     pnp_write(0x30, 0x01);
diff --git a/src/board/system76/darp5/smfi.c b/src/board/system76/darp5/smfi.c
new file mode 100644
index 0000000..ac1590b
--- /dev/null
+++ b/src/board/system76/darp5/smfi.c
@@ -0,0 +1,98 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <common/macro.h>
+#include <common/version.h>
+
+// Shared memory host semaphore
+volatile uint8_t __xdata __at(0x1022) SMHSR;
+// Host RAM window control
+volatile uint8_t __xdata __at(0x105A) HRAMWC;
+// Host RAM window 0 base address
+volatile uint8_t __xdata __at(0x105B) HRAMW0BA;
+// Host RAM window 1 base address
+volatile uint8_t __xdata __at(0x105C) HRAMW1BA;
+// Host RAM window 0 access allow size
+volatile uint8_t __xdata __at(0x105D) HRAMW0AAS;
+// Host RAM window 1 access allow size
+volatile uint8_t __xdata __at(0x105E) HRAMW1AAS;
+
+static volatile uint8_t __xdata __at(0xC00) smfi_cmd[256];
+static volatile uint8_t __xdata __at(0xD00) smfi_dbg[256];
+
+enum SmfiCmd {
+    SMFI_CMD_NONE = 0,
+    SMFI_CMD_PROBE = 1,
+    SMFI_CMD_BOARD = 2,
+    SMFI_CMD_VERSION = 3,
+    //TODO
+};
+
+enum SmfiRes {
+    SMFI_RES_OK = 0,
+    SMFI_RES_ERR = 1,
+    //TODO
+};
+
+void smfi_init(void) {
+    int i;
+
+    // Clear command region
+    for (i = 0; i < ARRAY_SIZE(smfi_cmd); i++) {
+        smfi_cmd[i] = 0x00;
+    }
+
+    // Clear debug region
+    for (i = 0; i < ARRAY_SIZE(smfi_dbg); i++) {
+        smfi_dbg[i] = 0x00;
+    }
+
+
+    // H2RAM window 0 address 0xC00 - 0xCFF, read/write
+    HRAMW0BA = 0xC0;
+    HRAMW0AAS = 0x04;
+
+    // H2RAM window 1 address 0xD00 - 0xDFF, read/write
+    HRAMW1BA = 0xD0;
+    HRAMW1AAS = 0x04;
+
+    // Enable H2RAM window 0 and 1 using LPC I/O
+    HRAMWC |= 0x13;
+}
+
+void smfi_event(void) {
+    if (smfi_cmd[0]) {
+        // Default to success
+        smfi_cmd[1] = SMFI_RES_OK;
+
+        switch (smfi_cmd[0]) {
+            case SMFI_CMD_PROBE:
+                // Signature
+                smfi_cmd[2] = 0x76;
+                smfi_cmd[3] = 0xEC;
+                // Version
+                smfi_cmd[4] = 0x01;
+                break;
+            case SMFI_CMD_BOARD:
+                strncpy(&smfi_cmd[2], board(), ARRAY_SIZE(smfi_cmd) - 2);
+                break;
+            case SMFI_CMD_VERSION:
+                strncpy(&smfi_cmd[2], version(), ARRAY_SIZE(smfi_cmd) - 2);
+                break;
+        }
+
+        // Mark command as finished
+        smfi_cmd[0] = SMFI_CMD_NONE;
+    }
+
+    if (smfi_dbg[0]) {
+        int i;
+        for(i = 1; (i <= (int)smfi_dbg[0]) && (i < ARRAY_SIZE(smfi_dbg)); i++) {
+            putchar(smfi_dbg[i]);
+        }
+
+        // Mark debug transaction as complete
+        smfi_dbg[0] = 0;
+    }
+}
diff --git a/src/board/system76/galp3-c/board.mk b/src/board/system76/galp3-c/board.mk
index d1dfc77..83dced9 100644
--- a/src/board/system76/galp3-c/board.mk
+++ b/src/board/system76/galp3-c/board.mk
@@ -42,3 +42,7 @@ flash: $(BUILD)/ec.rom
 isp: $(BUILD)/ec.rom
 	cargo build --manifest-path ecflash/Cargo.toml --example isp --release
 	sudo ecflash/target/release/examples/isp $<
+
+version:
+	cargo build --manifest-path ecflash/Cargo.toml --example smfi --release
+	sudo ecflash/target/release/examples/smfi
diff --git a/src/board/system76/galp3-c/include/board/smfi.h b/src/board/system76/galp3-c/include/board/smfi.h
new file mode 100644
index 0000000..532ef23
--- /dev/null
+++ b/src/board/system76/galp3-c/include/board/smfi.h
@@ -0,0 +1,7 @@
+#ifndef _BOARD_SMFI_H
+#define _BOARD_SMFI_H
+
+void smfi_init(void);
+void smfi_event(void);
+
+#endif // _BOARD_SMFI_H
diff --git a/src/board/system76/galp3-c/main.c b/src/board/system76/galp3-c/main.c
index 3809667..b3cab6b 100644
--- a/src/board/system76/galp3-c/main.c
+++ b/src/board/system76/galp3-c/main.c
@@ -18,6 +18,7 @@
 #include <board/ps2.h>
 #include <board/pwm.h>
 #include <board/smbus.h>
+#include <board/smfi.h>
 #include <common/debug.h>
 #include <common/macro.h>
 #include <common/version.h>
@@ -47,6 +48,7 @@ void init(void) {
     pmc_init();
     pwm_init();
     smbus_init();
+    smfi_init();
 
     //TODO: INTC
 }
@@ -115,7 +117,9 @@ void main(void) {
         }
         // Handles ACPI communication
         pmc_event(&PMC_1);
+        // AP/EC communication over SMFI
+        smfi_event();
         // Idle until next timer interrupt
-        PCON |= 1;
+        //Disabled until interrupts used: PCON |= 1;
     }
 }
diff --git a/src/board/system76/galp3-c/pnp.c b/src/board/system76/galp3-c/pnp.c
index 1146a87..6f9ab5b 100644
--- a/src/board/system76/galp3-c/pnp.c
+++ b/src/board/system76/galp3-c/pnp.c
@@ -41,6 +41,12 @@ void pnp_enable() {
     pnp_write(0x07, 0x05);
     pnp_write(0x30, 0x01);
 
+    // Enable SMFI
+    pnp_write(0x07, 0x0F);
+    pnp_write(0xF5, 0x00);
+    pnp_write(0xF6, 0x01);
+    pnp_write(0x30, 0x01);
+
     // Enable SWUC
     pnp_write(0x07, 0x04);
     pnp_write(0x30, 0x01);
diff --git a/src/board/system76/galp3-c/smfi.c b/src/board/system76/galp3-c/smfi.c
new file mode 100644
index 0000000..ac1590b
--- /dev/null
+++ b/src/board/system76/galp3-c/smfi.c
@@ -0,0 +1,98 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <common/macro.h>
+#include <common/version.h>
+
+// Shared memory host semaphore
+volatile uint8_t __xdata __at(0x1022) SMHSR;
+// Host RAM window control
+volatile uint8_t __xdata __at(0x105A) HRAMWC;
+// Host RAM window 0 base address
+volatile uint8_t __xdata __at(0x105B) HRAMW0BA;
+// Host RAM window 1 base address
+volatile uint8_t __xdata __at(0x105C) HRAMW1BA;
+// Host RAM window 0 access allow size
+volatile uint8_t __xdata __at(0x105D) HRAMW0AAS;
+// Host RAM window 1 access allow size
+volatile uint8_t __xdata __at(0x105E) HRAMW1AAS;
+
+static volatile uint8_t __xdata __at(0xC00) smfi_cmd[256];
+static volatile uint8_t __xdata __at(0xD00) smfi_dbg[256];
+
+enum SmfiCmd {
+    SMFI_CMD_NONE = 0,
+    SMFI_CMD_PROBE = 1,
+    SMFI_CMD_BOARD = 2,
+    SMFI_CMD_VERSION = 3,
+    //TODO
+};
+
+enum SmfiRes {
+    SMFI_RES_OK = 0,
+    SMFI_RES_ERR = 1,
+    //TODO
+};
+
+void smfi_init(void) {
+    int i;
+
+    // Clear command region
+    for (i = 0; i < ARRAY_SIZE(smfi_cmd); i++) {
+        smfi_cmd[i] = 0x00;
+    }
+
+    // Clear debug region
+    for (i = 0; i < ARRAY_SIZE(smfi_dbg); i++) {
+        smfi_dbg[i] = 0x00;
+    }
+
+
+    // H2RAM window 0 address 0xC00 - 0xCFF, read/write
+    HRAMW0BA = 0xC0;
+    HRAMW0AAS = 0x04;
+
+    // H2RAM window 1 address 0xD00 - 0xDFF, read/write
+    HRAMW1BA = 0xD0;
+    HRAMW1AAS = 0x04;
+
+    // Enable H2RAM window 0 and 1 using LPC I/O
+    HRAMWC |= 0x13;
+}
+
+void smfi_event(void) {
+    if (smfi_cmd[0]) {
+        // Default to success
+        smfi_cmd[1] = SMFI_RES_OK;
+
+        switch (smfi_cmd[0]) {
+            case SMFI_CMD_PROBE:
+                // Signature
+                smfi_cmd[2] = 0x76;
+                smfi_cmd[3] = 0xEC;
+                // Version
+                smfi_cmd[4] = 0x01;
+                break;
+            case SMFI_CMD_BOARD:
+                strncpy(&smfi_cmd[2], board(), ARRAY_SIZE(smfi_cmd) - 2);
+                break;
+            case SMFI_CMD_VERSION:
+                strncpy(&smfi_cmd[2], version(), ARRAY_SIZE(smfi_cmd) - 2);
+                break;
+        }
+
+        // Mark command as finished
+        smfi_cmd[0] = SMFI_CMD_NONE;
+    }
+
+    if (smfi_dbg[0]) {
+        int i;
+        for(i = 1; (i <= (int)smfi_dbg[0]) && (i < ARRAY_SIZE(smfi_dbg)); i++) {
+            putchar(smfi_dbg[i]);
+        }
+
+        // Mark debug transaction as complete
+        smfi_dbg[0] = 0;
+    }
+}
diff --git a/src/board/system76/lemp9/board.mk b/src/board/system76/lemp9/board.mk
index ea1be51..5ff2249 100644
--- a/src/board/system76/lemp9/board.mk
+++ b/src/board/system76/lemp9/board.mk
@@ -45,3 +45,7 @@ flash: $(BUILD)/ec.rom
 isp: $(BUILD)/ec.rom
 	cargo build --manifest-path ecflash/Cargo.toml --example isp --release
 	sudo ecflash/target/release/examples/isp $<
+
+version:
+	cargo build --manifest-path ecflash/Cargo.toml --example smfi --release
+	sudo ecflash/target/release/examples/smfi