diff --git a/framework/resources.c b/framework/resources.c
index 2ff7035..6898028 100644
--- a/framework/resources.c
+++ b/framework/resources.c
@@ -73,19 +73,12 @@ error_t rsc_claim(Unit *unit, Resource rsc)
     assert_param(rsc < RESOURCE_COUNT);
     assert_param(unit != NULL);
 
+    dbg("%s claims %s", unit->name, rsc_get_name(rsc));
+
     if (RSC_IS_HELD(global_rscmap, rsc)) {
         // this whole branch is just reporting the error
 
         Unit *holder = ureg_get_rsc_owner(rsc);
-
-        if (holder == NULL) {
-            // It must be one of the dummy built-in units
-            if (RSC_IS_HELD(UNIT_SYSTEM.resources, rsc))
-                holder = &UNIT_SYSTEM;
-            else if (RSC_IS_HELD(UNIT_PLATFORM.resources, rsc))
-                holder = &UNIT_SYSTEM;
-        }
-
         assert_param(holder != NULL);
 
         dbg("ERROR!! Unit %s failed to claim resource %s, already held by %s!",
@@ -154,6 +147,8 @@ void rsc_free(Unit *unit, Resource rsc)
     assert_param(rsc_initialized);
     assert_param(rsc < RESOURCE_COUNT);
 
+    dbg("Free resource %s", rsc_get_name(rsc));
+
     if (RSC_IS_FREE(global_rscmap, rsc)) return;
 
     // free it in any unit that holds it
@@ -197,7 +192,8 @@ void rsc_free_range(Unit *unit, Resource rsc0, Resource rsc1)
 }
 
 /**
- * Tear down a unit - release all resources owned by the unit
+ * Tear down a unit - release all resources owned by the unit.
+ * Also de-init all GPIOs
  *
  * @param unit - unit to tear down; free only resources claimed by this unit
  */
@@ -206,6 +202,8 @@ void rsc_teardown(Unit *unit)
     assert_param(rsc_initialized);
     assert_param(unit != NULL);
 
+    deinit_unit_pins(unit);
+
     for (uint32_t i = 0; i < RSCMAP_LEN; i++) {
         global_rscmap[i] &= ~unit->resources[i];
         unit->resources[i] = 0;
diff --git a/framework/unit_registry.c b/framework/unit_registry.c
index 79d7710..dda027f 100644
--- a/framework/unit_registry.c
+++ b/framework/unit_registry.c
@@ -355,14 +355,22 @@ static void export_unit_do(UlistEntry *li, IniWriter *iw)
 
     iw_section(iw, "%s:%s@%d", pUnit->driver->name, pUnit->name, (int)pUnit->callsign);
     if (pUnit->status != E_SUCCESS) {
-        // special message for failed unit die to resource
-        if (pUnit->status == E_RESOURCE_NOT_AVAILABLE) {
-            iw_comment(iw, "!!! %s not available, already held by %s",
-                       rsc_get_name(pUnit->failed_rsc),
-                       rsc_get_owner_name(pUnit->failed_rsc));
-        } else {
-            iw_comment(iw, "!!! %s", error_get_message(pUnit->status));
+        // temporarily force comments ON
+        bool sc = SystemSettings.ini_comments;
+        SystemSettings.ini_comments = true;
+        {
+            // special message for failed unit die to resource
+            if (pUnit->status == E_RESOURCE_NOT_AVAILABLE) {
+                iw_comment(iw, "!!! %s not available, already held by %s",
+                           rsc_get_name(pUnit->failed_rsc),
+                           rsc_get_owner_name(pUnit->failed_rsc));
+            }
+            else {
+                iw_comment(iw, "!!! %s", error_get_message(pUnit->status));
+            }
+            iw_cmt_newline(iw);
         }
+        SystemSettings.ini_comments = sc;
     }
     pUnit->driver->cfgWriteIni(pUnit, iw);
 }
@@ -540,5 +548,9 @@ Unit *ureg_get_rsc_owner(Resource resource)
         }
         li = li->next;
     }
+
+    if (RSC_IS_HELD(UNIT_SYSTEM.resources, resource)) return &UNIT_SYSTEM;
+    if (RSC_IS_HELD(UNIT_PLATFORM.resources, resource)) return &UNIT_PLATFORM;
+
     return NULL;
 }
diff --git a/platform/pin_utils.c b/platform/pin_utils.c
index db1a50d..a9a5af0 100644
--- a/platform/pin_utils.c
+++ b/platform/pin_utils.c
@@ -260,3 +260,14 @@ uint16_t port_pack(uint16_t spread, uint16_t mask)
     }
     return result;
 }
+
+void deinit_unit_pins(Unit *unit)
+{
+    for (uint32_t rsc = R_PA0; rsc <= R_PF0; rsc++) {
+        if (RSC_IS_HELD(unit->resources, rsc)) {
+            GPIO_TypeDef *port = port_periphs[(rsc-R_PA0) / 16];
+            uint32_t ll_pin = ll_pins[(rsc-R_PA0)%16];
+            LL_GPIO_SetPinMode(port, ll_pin, LL_GPIO_MODE_ANALOG);
+        }
+    }
+}
diff --git a/platform/pin_utils.h b/platform/pin_utils.h
index ead2b34..a996cde 100644
--- a/platform/pin_utils.h
+++ b/platform/pin_utils.h
@@ -68,4 +68,11 @@ uint16_t port_spread(uint16_t packed, uint16_t mask);
  */
 uint16_t port_pack(uint16_t spread, uint16_t mask);
 
+/**
+ * Set all GPIO resources held by unit to analog
+ *
+ * @param unit - holding unit
+ */
+void deinit_unit_pins(Unit *unit);
+
 #endif //GEX_PIN_UTILS_H
diff --git a/units/digital_in/unit_din.c b/units/digital_in/unit_din.c
index 01c321b..1071e57 100644
--- a/units/digital_in/unit_din.c
+++ b/units/digital_in/unit_din.c
@@ -161,23 +161,7 @@ static error_t DI_init(Unit *unit)
 /** Tear down the unit */
 static void DI_deInit(Unit *unit)
 {
-    struct priv *priv = unit->data;
-
-    if (unit->status == E_SUCCESS) {
-        assert_param(priv->port);
-
-        bool suc = true;
-        uint16_t mask = 1;
-        for (int i = 0; i < 16; i++, mask <<= 1) {
-            if (priv->pins & mask) {
-                uint32_t ll_pin = pin2ll((uint8_t) i, &suc);
-                assert_param(suc); // this should never fail if we got this far
-
-                // configure the pin as analog
-                LL_GPIO_SetPinMode(priv->port, ll_pin, LL_GPIO_MODE_ANALOG);
-            }
-        }
-    }
+    // pins are de-inited during teardown
 
     // Release all resources
     rsc_teardown(unit);
diff --git a/units/digital_out/unit_dout.c b/units/digital_out/unit_dout.c
index cb6f48d..5c1671d 100644
--- a/units/digital_out/unit_dout.c
+++ b/units/digital_out/unit_dout.c
@@ -151,25 +151,7 @@ static error_t DO_init(Unit *unit)
 /** Tear down the unit */
 static void DO_deInit(Unit *unit)
 {
-    struct priv *priv = unit->data;
-
-    // de-init the pins only if inited correctly
-    if (unit->status == E_SUCCESS) {
-        assert_param(priv->port);
-
-        bool suc = true;
-        uint16_t mask = 1;
-        for (int i = 0; i < 16; i++, mask <<= 1) {
-            if (priv->pins & mask) {
-
-                uint32_t ll_pin = pin2ll((uint8_t) i, &suc);
-                assert_param(suc); // this should never fail if we got this far
-
-                // configure the pin as analog
-                LL_GPIO_SetPinMode(priv->port, ll_pin, LL_GPIO_MODE_ANALOG);
-            }
-        }
-    }
+    // pins are de-inited during teardown
 
     // Release all resources
     rsc_teardown(unit);
diff --git a/units/i2c/unit_i2c.c b/units/i2c/unit_i2c.c
index 796691a..ba5060b 100644
--- a/units/i2c/unit_i2c.c
+++ b/units/i2c/unit_i2c.c
@@ -2,6 +2,7 @@
 // Created by MightyPork on 2018/01/02.
 //
 
+#include <framework/system_settings.h>
 #include "comm/messages.h"
 #include "unit_base.h"
 #include "utils/avrlibc.h"
@@ -12,6 +13,8 @@
 /** Private data structure */
 struct priv {
     uint8_t periph_num; //!< 1 or 2
+    uint8_t remap;      //!< I2C remap option
+
     bool anf;    //!< Enable analog noise filter
     uint8_t dnf; //!< Enable digital noise filter (1-15 ... max spike width)
     uint8_t speed; //!< 0 - Standard, 1 - Fast, 2 - Fast+
@@ -63,6 +66,9 @@ static error_t UI2C_loadIni(Unit *unit, const char *key, const char *value)
     if (streq(key, "device")) {
         priv->periph_num = (uint8_t) avr_atoi(value);
     }
+    else if (streq(key, "remap")) {
+        priv->remap = (uint8_t) avr_atoi(value);
+    }
     else if (streq(key, "analog-filter")) {
         priv->anf = str_parse_yn(value, &suc);
     }
@@ -88,6 +94,22 @@ static void UI2C_writeIni(Unit *unit, IniWriter *iw)
     iw_comment(iw, "Peripheral number (I2Cx)");
     iw_entry(iw, "device", "%d", (int)priv->periph_num);
 
+    iw_comment(iw, "Pin mappings (SCL,SDA)");
+#if GEX_PLAT_F072_DISCOVERY
+    iw_comment(iw, " I2C1: (0) B6,B7    (1) B8,B9");
+    iw_comment(iw, " I2C2: (0) B10,B11  (1) B13,B14");
+#elif GEX_PLAT_F103_BLUEPILL
+    #error "NO IMPL"
+#elif GEX_PLAT_F303_DISCOVERY
+    #error "NO IMPL"
+#elif GEX_PLAT_F407_DISCOVERY
+    #error "NO IMPL"
+#else
+    #error "BAD PLATFORM!"
+#endif
+    iw_entry(iw, "remap", "%d", (int)priv->remap);
+
+    iw_cmt_newline(iw);
     iw_comment(iw, "Speed: 1-Standard, 2-Fast, 3-Fast+");
     iw_entry(iw, "speed", "%d", (int)priv->speed);
 
@@ -157,17 +179,38 @@ static error_t UI2C_init(Unit *unit)
 #if GEX_PLAT_F072_DISCOVERY
     // scl - 6 or 8 for I2C1, 10 for I2C2
     // sda - 7 or 9 for I2C1, 11 for I2C2
-    portname = 'B';
-
     if (priv->periph_num == 1) {
-        pin_scl = 8;
-        pin_sda = 9;
+        // I2C1
+        if (priv->remap == 0) {
+            af_i2c = LL_GPIO_AF_1;
+            portname = 'B';
+            pin_scl = 6;
+            pin_sda = 7;
+        } else if (priv->remap == 1) {
+            af_i2c = LL_GPIO_AF_1;
+            portname = 'B';
+            pin_scl = 8;
+            pin_sda = 9;
+        } else {
+            return E_BAD_CONFIG;
+        }
     } else {
-        pin_scl = 10;
-        pin_sda = 12;
+        // I2C2
+        if (priv->remap == 0) {
+            af_i2c = LL_GPIO_AF_1;
+            portname = 'B';
+            pin_scl = 10;
+            pin_sda = 11;
+        } else if (priv->remap == 1) {
+            af_i2c = LL_GPIO_AF_5;
+            portname = 'B';
+            pin_scl = 13;
+            pin_sda = 14;
+        } else {
+            return E_BAD_CONFIG;
+        }
     }
 
-    af_i2c = LL_GPIO_AF_1;
     if (priv->speed == 1)
         timing = 0x00301D2B; // Standard
     else if (priv->speed == 2)
@@ -244,7 +287,6 @@ static void UI2C_deInit(Unit *unit)
     // de-init the pins & peripheral only if inited correctly
     if (unit->status == E_SUCCESS) {
         assert_param(priv->periph);
-        assert_param(priv->port);
 
         LL_I2C_DeInit(priv->periph);
 
@@ -253,9 +295,6 @@ static void UI2C_deInit(Unit *unit)
         } else {
             __HAL_RCC_I2C2_CLK_DISABLE();
         }
-
-        LL_GPIO_SetPinMode(priv->port, priv->ll_pin_sda, LL_GPIO_MODE_ANALOG);
-        LL_GPIO_SetPinMode(priv->port, priv->ll_pin_scl, LL_GPIO_MODE_ANALOG);
     }
 
     // Release all resources
diff --git a/units/neopixel/unit_neopixel.c b/units/neopixel/unit_neopixel.c
index b5b1a21..585fdf2 100644
--- a/units/neopixel/unit_neopixel.c
+++ b/units/neopixel/unit_neopixel.c
@@ -121,13 +121,7 @@ static error_t Npx_init(Unit *unit)
 /** Tear down the unit */
 static void Npx_deInit(Unit *unit)
 {
-    struct priv *priv = unit->data;
-
-    if (unit->status == E_SUCCESS) {
-        assert_param(priv->port);
-        // configure the pin as analog
-        LL_GPIO_SetPinMode(priv->port, priv->ll_pin, LL_GPIO_MODE_ANALOG);
-    }
+    // pins are de-inited during teardown
 
     // Release all resources
     rsc_teardown(unit);
diff --git a/units/spi/unit_spi.c b/units/spi/unit_spi.c
index 055c396..a315d50 100644
--- a/units/spi/unit_spi.c
+++ b/units/spi/unit_spi.c
@@ -124,7 +124,6 @@ static void USPI_writeIni(Unit *unit, IniWriter *iw)
 {
     struct priv *priv = unit->data;
 
-    iw_cmt_newline(iw);
     iw_comment(iw, "Peripheral number (SPIx)");
     iw_entry(iw, "device", "%d", (int)priv->periph_num);
 
@@ -228,7 +227,6 @@ static error_t USPI_init(Unit *unit)
 
     // TODO
 #if GEX_PLAT_F072_DISCOVERY
-
     // SPI1 - many options
     // sck, miso, mosi, af
 
@@ -394,8 +392,6 @@ static void USPI_deInit(Unit *unit)
     // de-init the pins & peripheral only if inited correctly
     if (unit->status == E_SUCCESS) {
         assert_param(priv->periph);
-        assert_param(priv->spi_port);
-        assert_param(priv->ssn_port);
 
         LL_SPI_DeInit(priv->periph);
 
@@ -404,22 +400,6 @@ static void USPI_deInit(Unit *unit)
         } else {
             __HAL_RCC_SPI2_CLK_DISABLE();
         }
-
-        LL_GPIO_SetPinMode(priv->spi_port, priv->ll_pin_mosi, LL_GPIO_MODE_ANALOG);
-        LL_GPIO_SetPinMode(priv->spi_port, priv->ll_pin_mosi, LL_GPIO_MODE_ANALOG);
-        LL_GPIO_SetPinMode(priv->spi_port, priv->ll_pin_sck, LL_GPIO_MODE_ANALOG);
-
-        // de-init all SSN pins
-        bool suc = true;
-        uint16_t mask = 1;
-        for (int i = 0; i < 16; i++, mask <<= 1) {
-            if (priv->ssn_pins & mask) {
-                uint32_t ll_pin = pin2ll((uint8_t) i, &suc);
-                assert_param(suc);
-                // configure the pin as analog
-                LL_GPIO_SetPinMode(priv->ssn_port, ll_pin, LL_GPIO_MODE_ANALOG);
-            }
-        }
     }
 
     // Release all resources