diff --git a/power.sh b/power.sh
index f5e7418..3029913 100755
--- a/power.sh
+++ b/power.sh
@@ -2,13 +2,10 @@
 
 set -e
 
-./ectool.sh info
-sudo modprobe msr
-
-header=1
-if [ -e power.csv ]
+has_ec=0
+if ./ectool.sh info 2> /dev/null
 then
-    header=0
+    has_ec=1
 fi
 
 has_dgpu=0
@@ -17,6 +14,14 @@ then
     has_dgpu=1
 fi
 
+sudo modprobe msr
+
+header=1
+if [ -e power.csv ]
+then
+    header=0
+fi
+
 while true
 do
     if [ "${header}" == "1" ]
@@ -29,12 +34,18 @@ do
         F="${F}\tCPU C"
         F="${F}\tCPU TCC"
         F="${F}\tCPU TJM"
-        F="${F}\tCPU FAN"
+        if [ "${has_ec}" == "1" ]
+        then
+            F="${F}\tCPU FAN"
+        fi
         if [ "${has_dgpu}" == "1" ]
         then
             F="${F}\tGPU W"
             F="${F}\tGPU C"
-            F="${F}\tGPU FAN"
+            if [ "${has_ec}" == "1" ]
+            then
+                F="${F}\tGPU FAN"
+            fi
         fi
     else
         F="$(date "+%T")"
@@ -71,9 +82,12 @@ do
         F="${F}\t$(printf "%d" "${TCC}")"
         F="${F}\t$(printf "%d" "${TJMAX}")"
 
-        D="$(sudo tool/target/release/system76_ectool fan 0)"
-        P="$(echo "(${D} * 100)/255" | bc -lq)"
-        F="${F}\t$(printf "%.0f" "${P}")"
+        if [ "${has_ec}" == "1" ]
+        then
+            D="$(sudo tool/target/release/system76_ectool fan 0)"
+            P="$(echo "(${D} * 100)/255" | bc -lq)"
+            F="${F}\t$(printf "%.0f" "${P}")"
+        fi
 
         if [ "${has_dgpu}" == "1" ]
         then
@@ -83,9 +97,12 @@ do
             DGPU_T="$(nvidia-smi --query-gpu=temperature.gpu --format=csv,noheader)"
             F="${F}\t${DGPU_T}"
 
-            D="$(sudo tool/target/release/system76_ectool fan 1)"
-            P="$(echo "(${D} * 100)/255" | bc -lq)"
-            F="${F}\t$(printf "%.0f" "${P}")"
+            if [ "${has_ec}" == "1" ]
+            then
+                D="$(sudo tool/target/release/system76_ectool fan 1)"
+                P="$(echo "(${D} * 100)/255" | bc -lq)"
+                F="${F}\t$(printf "%.0f" "${P}")"
+            fi
         fi
     fi
 
diff --git a/src/board/system76/addw2/board.c b/src/board/system76/addw2/board.c
index 5c3375d..a99e60a 100644
--- a/src/board/system76/addw2/board.c
+++ b/src/board/system76/addw2/board.c
@@ -4,6 +4,7 @@
 #include <board/dgpu.h>
 #include <board/gpio.h>
 #include <board/kbc.h>
+#include <board/peci.h>
 #include <board/power.h>
 #include <common/debug.h>
 
@@ -25,10 +26,36 @@ void board_init(void) {
     dgpu_init();
 }
 
+// Set PL4 using PECI
+static int set_power_limit(uint8_t watts) {
+    return peci_wr_pkg_config(
+        60, // index
+        0, // param
+        ((uint32_t)watts) * 8
+    );
+}
+
 void board_event(void) {
+    bool acin = !gpio_get(&ACIN_N);
+    gpio_set(&AC_PRESENT, acin);
+
+    static uint8_t last_power_limit = 0;
+    if (power_state == POWER_STATE_S0) {
+        uint8_t power_limit = acin ? POWER_LIMIT_AC : POWER_LIMIT_DC;
+        if (power_limit != last_power_limit) {
+            int res = set_power_limit(power_limit);
+            DEBUG("set_power_limit %d = %d\n", power_limit, res);
+            if (res >= 0) {
+                last_power_limit = power_limit;
+            } else {
+                ERROR("set_power_limit failed: %X\n", -res);
+            }
+        }
+    } else {
+        last_power_limit = 0;
+    }
+
     if (main_cycle == 0) {
-        bool acin = !gpio_get(&ACIN_N);
-        gpio_set(&AC_PRESENT, acin);
         if (acin) {
             // Discharging (no AC adapter)
             gpio_set(&LED_BAT_CHG, false);
diff --git a/src/board/system76/addw2/board.mk b/src/board/system76/addw2/board.mk
index 96372b4..fe9e61f 100644
--- a/src/board/system76/addw2/board.mk
+++ b/src/board/system76/addw2/board.mk
@@ -31,6 +31,11 @@ CFLAGS+=\
 	-DCHARGER_CHARGE_VOLTAGE=12600 \
 	-DCHARGER_INPUT_CURRENT=11800
 
+# Set CPU power limits in watts
+CFLAGS+=\
+	-DPOWER_LIMIT_AC=180 \
+	-DPOWER_LIMIT_DC=28
+
 # Enable debug logging over keyboard parallel port
 #CFLAGS+=-DPARPORT_DEBUG
 
diff --git a/src/board/system76/addw2/dgpu.c b/src/board/system76/addw2/dgpu.c
index bc033a7..916c748 100644
--- a/src/board/system76/addw2/dgpu.c
+++ b/src/board/system76/addw2/dgpu.c
@@ -116,7 +116,7 @@ void dgpu_init(void) {
 }
 
 void dgpu_event(void) {
-    if (power_state == POWER_STATE_S0 && gpio_get(&DGPU_PWR_EN)) {
+    if (power_state == POWER_STATE_S0 && gpio_get(&DGPU_PWR_EN) && !gpio_get(&GC6_FB_EN)) {
         // Use I2CS if in S0 state
         int8_t rlts;
         int res = i2c_get(&I2C_DGPU, 0x4F, 0x00, &rlts, 1);
diff --git a/src/board/system76/addw2/gpio.c b/src/board/system76/addw2/gpio.c
index a76073a..eac9c04 100644
--- a/src/board/system76/addw2/gpio.c
+++ b/src/board/system76/addw2/gpio.c
@@ -11,6 +11,7 @@ struct Gpio __code DD_ON =          GPIO(E, 4);
 struct Gpio __code DGPU_PWR_EN =    GPIO(H, 4);
 struct Gpio __code EC_EN =          GPIO(B, 6); // renamed to SUSBC_EN
 struct Gpio __code EC_RSMRST_N =    GPIO(E, 5);
+struct Gpio __code GC6_FB_EN =      GPIO(H, 3);
 struct Gpio __code LED_ACIN =       GPIO(C, 7);
 struct Gpio __code LED_AIRPLANE_N = GPIO(H, 7);
 struct Gpio __code LED_CAP_N =      GPIO(J, 2);
diff --git a/src/board/system76/addw2/include/board/gpio.h b/src/board/system76/addw2/include/board/gpio.h
index 5c84811..4fb84b1 100644
--- a/src/board/system76/addw2/include/board/gpio.h
+++ b/src/board/system76/addw2/include/board/gpio.h
@@ -22,6 +22,7 @@ extern struct Gpio __code DD_ON;
 extern struct Gpio __code DGPU_PWR_EN;
 extern struct Gpio __code EC_EN; // renamed to SUSBC_EN
 extern struct Gpio __code EC_RSMRST_N;
+extern struct Gpio __code GC6_FB_EN;
 extern struct Gpio __code LED_ACIN;
 extern struct Gpio __code LED_AIRPLANE_N;
 extern struct Gpio __code LED_CAP_N;
diff --git a/src/board/system76/common/include/board/peci.h b/src/board/system76/common/include/board/peci.h
index c447300..9e7015c 100644
--- a/src/board/system76/common/include/board/peci.h
+++ b/src/board/system76/common/include/board/peci.h
@@ -10,6 +10,7 @@ extern uint8_t peci_tcontrol;
 extern uint8_t peci_tjmax;
 
 void peci_init(void);
+int peci_wr_pkg_config(uint8_t index, uint16_t param, uint32_t data);
 void peci_event(void);
 
 #endif // _BOARD_PECI_H
diff --git a/src/board/system76/common/peci.c b/src/board/system76/common/peci.c
index 04d9a66..8211713 100644
--- a/src/board/system76/common/peci.c
+++ b/src/board/system76/common/peci.c
@@ -123,6 +123,57 @@ void peci_init(void) {
     PADCTLR = 0x02;
 }
 
+// Returns positive completion code on success, negative completion code or
+// negative (0x1000 | status register) on PECI hardware error
+int peci_wr_pkg_config(uint8_t index, uint16_t param, uint32_t data) {
+    // Wait for completion
+    while (HOSTAR & 1) {}
+    // Clear status
+    HOSTAR = HOSTAR;
+
+    // Enable PECI, clearing data fifo's, enable AW_FCS
+    HOCTLR = (1 << 5) | (1 << 3) | (1 << 1);
+    // Set address to default
+    HOTRADDR = 0x30;
+    // Set write length
+    HOWRLR = 10;
+    // Set read length
+    HORDLR = 1;
+    // Set command
+    HOCMDR = 0xA5;
+
+    // Write host ID
+    HOWRDR = 0;
+    // Write index
+    HOWRDR = index;
+    // Write param
+    HOWRDR = (uint8_t)param;
+    HOWRDR = (uint8_t)(param >> 8);
+    // Write data
+    HOWRDR = (uint8_t)data;
+    HOWRDR = (uint8_t)(data >> 8);
+    HOWRDR = (uint8_t)(data >> 16);
+    HOWRDR = (uint8_t)(data >> 24);
+
+    // Start transaction
+    HOCTLR |= 1;
+
+    // Wait for completion
+    while (HOSTAR & 1) {}
+
+    int status = (int)HOSTAR;
+    if (status & (1 << 1)) {
+        int cc = (int)HORDDR;
+        if (cc & 0x80) {
+            return -cc;
+        } else {
+            return cc;
+        }
+    } else {
+        return -(0x1000 | status);
+    }
+}
+
 // PECI information can be found here: https://www.intel.com/content/dam/www/public/us/en/documents/design-guides/core-i7-lga-2011-guide.pdf
 void peci_event(void) {
     if (power_state == POWER_STATE_S0) {
diff --git a/src/board/system76/gaze15/board.c b/src/board/system76/gaze15/board.c
index 35c3e08..d0b4df5 100644
--- a/src/board/system76/gaze15/board.c
+++ b/src/board/system76/gaze15/board.c
@@ -4,6 +4,7 @@
 #include <board/dgpu.h>
 #include <board/gpio.h>
 #include <board/kbc.h>
+#include <board/peci.h>
 #include <board/power.h>
 #include <common/debug.h>
 
@@ -26,10 +27,36 @@ void board_init(void) {
     dgpu_init();
 }
 
+// Set PL4 using PECI
+static int set_power_limit(uint8_t watts) {
+    return peci_wr_pkg_config(
+        60, // index
+        0, // param
+        ((uint32_t)watts) * 8
+    );
+}
+
 void board_event(void) {
+    bool acin = !gpio_get(&ACIN_N);
+    gpio_set(&AC_PRESENT, acin);
+
+    static uint8_t last_power_limit = 0;
+    if (power_state == POWER_STATE_S0) {
+        uint8_t power_limit = acin ? POWER_LIMIT_AC : POWER_LIMIT_DC;
+        if (power_limit != last_power_limit) {
+            int res = set_power_limit(power_limit);
+            DEBUG("set_power_limit %d = %d\n", power_limit, res);
+            if (res >= 0) {
+                last_power_limit = power_limit;
+            } else {
+                ERROR("set_power_limit failed: %X\n", -res);
+            }
+        }
+    } else {
+        last_power_limit = 0;
+    }
+
     if (main_cycle == 0) {
-        bool acin = !gpio_get(&ACIN_N);
-        gpio_set(&AC_PRESENT, acin);
         if (acin) {
             // Discharging (no AC adapter)
             gpio_set(&LED_BAT_CHG, false);
diff --git a/src/board/system76/gaze15/board.mk b/src/board/system76/gaze15/board.mk
index d92fc57..b275aa2 100644
--- a/src/board/system76/gaze15/board.mk
+++ b/src/board/system76/gaze15/board.mk
@@ -31,6 +31,11 @@ CFLAGS+=\
 	-DCHARGER_CHARGE_VOLTAGE=16800 \
 	-DCHARGER_INPUT_CURRENT=9230
 
+# Set CPU power limits in watts
+CFLAGS+=\
+	-DPOWER_LIMIT_AC=180 \
+	-DPOWER_LIMIT_DC=28
+
 # Enable debug logging over keyboard parallel port
 #CFLAGS+=-DPARPORT_DEBUG
 
diff --git a/src/board/system76/gaze15/dgpu.c b/src/board/system76/gaze15/dgpu.c
index bc033a7..916c748 100644
--- a/src/board/system76/gaze15/dgpu.c
+++ b/src/board/system76/gaze15/dgpu.c
@@ -116,7 +116,7 @@ void dgpu_init(void) {
 }
 
 void dgpu_event(void) {
-    if (power_state == POWER_STATE_S0 && gpio_get(&DGPU_PWR_EN)) {
+    if (power_state == POWER_STATE_S0 && gpio_get(&DGPU_PWR_EN) && !gpio_get(&GC6_FB_EN)) {
         // Use I2CS if in S0 state
         int8_t rlts;
         int res = i2c_get(&I2C_DGPU, 0x4F, 0x00, &rlts, 1);
diff --git a/src/board/system76/gaze15/gpio.c b/src/board/system76/gaze15/gpio.c
index 2fcb96c..ccefebd 100644
--- a/src/board/system76/gaze15/gpio.c
+++ b/src/board/system76/gaze15/gpio.c
@@ -11,6 +11,7 @@ struct Gpio __code CCD_EN =         GPIO(D, 1);
 struct Gpio __code DD_ON =          GPIO(E, 4);
 struct Gpio __code DGPU_PWR_EN =    GPIO(J, 2);
 struct Gpio __code EC_RSMRST_N =    GPIO(E, 5);
+struct Gpio __code GC6_FB_EN =      GPIO(J, 3);
 struct Gpio __code LED_ACIN =       GPIO(C, 7);
 struct Gpio __code LED_AIRPLANE_N = GPIO(H, 7);
 struct Gpio __code LED_BAT_CHG =    GPIO(H, 5);
diff --git a/src/board/system76/gaze15/include/board/gpio.h b/src/board/system76/gaze15/include/board/gpio.h
index cf568aa..784f910 100644
--- a/src/board/system76/gaze15/include/board/gpio.h
+++ b/src/board/system76/gaze15/include/board/gpio.h
@@ -23,6 +23,7 @@ extern struct Gpio __code DD_ON;
 extern struct Gpio __code DGPU_PWR_EN;
 #define HAVE_EC_EN 0
 extern struct Gpio __code EC_RSMRST_N;
+extern struct Gpio __code GC6_FB_EN;
 extern struct Gpio __code LED_ACIN;
 extern struct Gpio __code LED_AIRPLANE_N;
 extern struct Gpio __code LED_BAT_CHG;
diff --git a/src/board/system76/oryp6/board.c b/src/board/system76/oryp6/board.c
index 8da9045..e4182d2 100644
--- a/src/board/system76/oryp6/board.c
+++ b/src/board/system76/oryp6/board.c
@@ -4,6 +4,7 @@
 #include <board/dgpu.h>
 #include <board/gpio.h>
 #include <board/kbc.h>
+#include <board/peci.h>
 #include <board/power.h>
 #include <common/debug.h>
 
@@ -28,10 +29,36 @@ void board_init(void) {
     dgpu_init();
 }
 
+// Set PL4 using PECI
+static int set_power_limit(uint8_t watts) {
+    return peci_wr_pkg_config(
+        60, // index
+        0, // param
+        ((uint32_t)watts) * 8
+    );
+}
+
 void board_event(void) {
+    bool acin = !gpio_get(&ACIN_N);
+    gpio_set(&AC_PRESENT, acin);
+
+    static uint8_t last_power_limit = 0;
+    if (power_state == POWER_STATE_S0) {
+        uint8_t power_limit = acin ? POWER_LIMIT_AC : POWER_LIMIT_DC;
+        if (power_limit != last_power_limit) {
+            int res = set_power_limit(power_limit);
+            DEBUG("set_power_limit %d = %d\n", power_limit, res);
+            if (res >= 0) {
+                last_power_limit = power_limit;
+            } else {
+                ERROR("set_power_limit failed: %X\n", -res);
+            }
+        }
+    } else {
+        last_power_limit = 0;
+    }
+
     if (main_cycle == 0) {
-        bool acin = !gpio_get(&ACIN_N);
-        gpio_set(&AC_PRESENT, acin);
         if (acin) {
             // Discharging (no AC adapter)
             gpio_set(&LED_BAT_CHG, false);
diff --git a/src/board/system76/oryp6/board.mk b/src/board/system76/oryp6/board.mk
index 0fa8921..970d02e 100644
--- a/src/board/system76/oryp6/board.mk
+++ b/src/board/system76/oryp6/board.mk
@@ -31,6 +31,11 @@ CFLAGS+=\
 	-DCHARGER_CHARGE_VOLTAGE=16800 \
 	-DCHARGER_INPUT_CURRENT=13050
 
+# Set CPU power limits in watts
+CFLAGS+=\
+	-DPOWER_LIMIT_AC=180 \
+	-DPOWER_LIMIT_DC=28
+
 # Enable debug logging over keyboard parallel port
 #CFLAGS+=-DPARPORT_DEBUG