diff --git a/src/board/system76/common/espi.c b/src/board/system76/common/espi.c
index d5db493..d3211c8 100644
--- a/src/board/system76/common/espi.c
+++ b/src/board/system76/common/espi.c
@@ -183,6 +183,9 @@ void espi_event(void) {
                 VW_SET_DEBUG(VW_SUS_ACK_N, wire);
             }
         }
+        if (value & BIT(7)) {
+            DEBUG("VWIDX47 %X\n", VWIDX47);
+        }
     }
 
     // Detect when frequency changes
diff --git a/src/board/system76/common/include/board/peci.h b/src/board/system76/common/include/board/peci.h
index 7d6fb9f..e5b5cbf 100644
--- a/src/board/system76/common/include/board/peci.h
+++ b/src/board/system76/common/include/board/peci.h
@@ -3,12 +3,15 @@
 #ifndef _BOARD_PECI_H
 #define _BOARD_PECI_H
 
+#include <stdbool.h>
+
 #include <ec/peci.h>
 
 extern bool peci_on;
 extern int16_t peci_temp;
 
 void peci_init(void);
+bool peci_available(void);
 int16_t peci_wr_pkg_config(uint8_t index, uint16_t param, uint32_t data);
 uint8_t peci_get_fan_duty(void);
 
diff --git a/src/board/system76/common/peci.c b/src/board/system76/common/peci.c
index 6800450..b5d7301 100644
--- a/src/board/system76/common/peci.c
+++ b/src/board/system76/common/peci.c
@@ -10,10 +10,6 @@
 #include <ec/gpio.h>
 #include <ec/pwm.h>
 
-#ifndef USE_PECI_OVER_ESPI
-#define USE_PECI_OVER_ESPI 0
-#endif
-
 // Fan speed is the lowest requested over HEATUP seconds
 #ifndef BOARD_HEATUP
 #define BOARD_HEATUP 4
@@ -63,10 +59,18 @@ static struct Fan __code FAN = {
     .interpolate = SMOOTH_FANS != 0,
 };
 
-#if USE_PECI_OVER_ESPI
+#if CONFIG_BUS_ESPI
 
 void peci_init(void) {}
 
+// Returns true if peci is available
+bool peci_available(void) {
+    // PECI is available if PLTRST_N is high
+    // Do not wake CPU from C10 if HOST_C10 virtual wire is high
+    //TODO: wake CPU every 8 seconds following Intel recommendation?
+    return (vw_get(&VW_PLTRST_N) == VWS_HIGH) && (vw_get(&VW_HOST_C10) != VWS_HIGH);
+}
+
 // Returns true on success, false on error
 bool peci_get_temp(int16_t * data) {
     //TODO: Wait for completion?
@@ -130,15 +134,80 @@ bool peci_get_temp(int16_t * data) {
 // Returns positive completion code on success, negative completion code or
 // negative (0x1000 | status register) on PECI hardware error
 int16_t peci_wr_pkg_config(uint8_t index, uint16_t param, uint32_t data) {
-    //TODO: IMPLEMENT THIS STUB
-    DEBUG("peci_wr_pkg_config %02X, %04X, %08X\n", index, param, data);
-    index = index;
-    param = param;
-    data = data;
-    return 0;
+    //TODO: Wait for completion?
+    // Clear upstream status
+    ESUCTRL0 = ESUCTRL0;
+    // Clear OOB status
+    ESOCTRL0 = ESOCTRL0;
+
+    // Set upstream cycle type
+    ESUCTRL1 = ESUCTRL1_OOB;
+    // Set upstream tag / length[11:8]
+    ESUCTRL2 = 0;
+    // Set upstream length [7:0] (size of PECI data plus 3)
+    ESUCTRL3 = 16;
+
+    // Destination address (0x10 is PCH, left shifted by one)
+    UDB[0] = 0x10 << 1;
+    // Command code (0x01 is PECI)
+    UDB[1] = 0x01;
+    // Set byte count
+    UDB[2] = 13;
+    // Set source address (0x0F is EC, left shifted by one, or with 1)
+    UDB[3] = (0x0F << 1) | 1;
+    // PECI target address (0x30 is default)
+    UDB[4] = 0x30;
+    // PECI write length
+    UDB[5] = 10;
+    // PECI read length
+    UDB[6] = 1;
+    // PECI command (0xA5 = WrPkgConfig)
+    UDB[7] = 0xA5;
+
+    // Write host ID
+    UDB[8] = 0;
+    // Write index
+    UDB[9] = index;
+    // Write param
+    UDB[10] = (uint8_t)param;
+    UDB[11] = (uint8_t)(param >> 8);
+    // Write data
+    UDB[12] = (uint8_t)data;
+    UDB[13] = (uint8_t)(data >> 8);
+    UDB[14] = (uint8_t)(data >> 16);
+    UDB[15] = (uint8_t)(data >> 24);
+
+    // Set upstream enable
+    ESUCTRL0 |= ESUCTRL0_ENABLE;
+    // Set upstream go
+    ESUCTRL0 |= ESUCTRL0_GO;
+
+    // Wait until upstream done
+    while (!(ESUCTRL0 & ESUCTRL0_DONE)) {}
+
+    // Wait for response
+    //TODO: do this asynchronously to avoid delays?
+    while (!(ESOCTRL0 & ESOCTRL0_STATUS)) {}
+
+    // Read response length
+    uint8_t len = ESOCTRL4;
+    if (len >= 6) {
+        //TODO: verify packet type, handle PECI status
+
+        // Received enough data for status code
+        int16_t cc = (int16_t)PUTOOBDB[5];
+        if (cc & 0x80) {
+            return -cc;
+        } else {
+            return cc;
+        }
+    } else {
+        // Did not receive enough data
+        return -0x1000;
+    }
 }
 
-#else // USE_PECI_OVER_ESPI
+#else // CONFIG_BUS_ESPI
 
 void peci_init(void) {
     // Allow PECI pin to be used
@@ -150,6 +219,12 @@ void peci_init(void) {
     PADCTLR = 0x02;
 }
 
+// Returns true if peci is available
+bool peci_available(void) {
+    // PECI is available if PLTRST# is high
+    return gpio_get(&BUF_PLT_RST_N);
+}
+
 // Returns true on success, false on error
 bool peci_get_temp(int16_t * data) {
     // Wait for completion
@@ -236,21 +311,13 @@ int16_t peci_wr_pkg_config(uint8_t index, uint16_t param, uint32_t data) {
     }
 }
 
-#endif // USE_PECI_OVER_ESPI
+#endif // CONFIG_BUS_ESPI
 
 // 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
 uint8_t peci_get_fan_duty(void) {
     uint8_t duty;
 
-#if CONFIG_BUS_ESPI
-    // Use PECI if CPU is not in C10 sleep state
-    // HOST_C10 virtual wire is high when CPU is in C10 sleep state
-    peci_on = vw_get(&VW_HOST_C10) == VWS_LOW;
-#else // CONFIG_BUS_ESPI
-    // Use PECI if in S0 state
-    peci_on = power_state == POWER_STATE_S0;
-#endif // CONFIG_BUS_ESPI
-
+    peci_on = peci_available();
     if (peci_on) {
         int16_t peci_offset = 0;
         if (peci_get_temp(&peci_offset)) {
diff --git a/src/board/system76/common/power.c b/src/board/system76/common/power.c
index 1d9e403..e6b434d 100644
--- a/src/board/system76/common/power.c
+++ b/src/board/system76/common/power.c
@@ -338,13 +338,7 @@ static bool power_peci_limit(bool ac) {
 // Set the power draw limit depending on if on AC or DC power
 void power_set_limit(void) {
     static bool last_power_limit_ac = true;
-    // We don't use power_state because the latency needs to be low
-#if CONFIG_BUS_ESPI
-    // HOST_C10 virtual wire is high when CPU is in C10 sleep state
-    if (vw_get(&VW_HOST_C10) == VWS_LOW) {
-#else // CONFIG_BUS_ESPI
-    if (gpio_get(&BUF_PLT_RST_N)) {
-#endif // CONFIG_BUS_ESPI
+    if (peci_available()) {
         bool ac = !gpio_get(&ACIN_N);
         if (last_power_limit_ac != ac) {
             if (power_peci_limit(ac)) {
diff --git a/src/board/system76/oryp11/board.mk b/src/board/system76/oryp11/board.mk
index 6ddbfda..5ee8b19 100644
--- a/src/board/system76/oryp11/board.mk
+++ b/src/board/system76/oryp11/board.mk
@@ -34,9 +34,6 @@ CFLAGS+=\
 	-DCHARGER_CHARGE_VOLTAGE=17600 \
 	-DCHARGER_INPUT_CURRENT=11500
 
-# Use PECI over ESPI
-CFLAGS+=-DUSE_PECI_OVER_ESPI=1
-
 # Set CPU power limits in watts
 CFLAGS+=\
 	-DPOWER_LIMIT_AC=230 \