diff --git a/framework/resources.c b/framework/resources.c
index 6898028..bcd985d 100644
--- a/framework/resources.c
+++ b/framework/resources.c
@@ -136,6 +136,15 @@ error_t rsc_claim_gpios(Unit *unit, char port_name, uint16_t pins)
     return E_SUCCESS;
 }
 
+error_t rsc_claim_pin(Unit *unit, char port_name, uint8_t pin)
+{
+    bool suc = true;
+    Resource rsc = pin2resource(port_name,  pin, &suc);
+    if (!suc) return E_BAD_CONFIG;
+    TRY(rsc_claim(unit, rsc));
+    return E_SUCCESS;
+}
+
 /**
  * Free a resource for other use
  *
diff --git a/framework/resources.h b/framework/resources.h
index 8290cf4..cd39c3c 100644
--- a/framework/resources.h
+++ b/framework/resources.h
@@ -13,6 +13,7 @@
 
 void rsc_init_registry(void);
 
+error_t rsc_claim_pin(Unit *unit, char port_name, uint8_t pin);
 error_t rsc_claim(Unit *unit, Resource rsc);
 error_t rsc_claim_range(Unit *unit, Resource rsc0, Resource rsc1);
 /**
diff --git a/platform/pin_utils.c b/platform/pin_utils.c
index a9a5af0..58a623c 100644
--- a/platform/pin_utils.c
+++ b/platform/pin_utils.c
@@ -271,3 +271,43 @@ void deinit_unit_pins(Unit *unit)
         }
     }
 }
+
+
+error_t configure_gpio_alternate(char port_name, uint8_t pin_num, uint32_t af)
+{
+    bool suc = true;
+    GPIO_TypeDef *port = port2periph(port_name, &suc);
+    uint32_t ll_pin = pin2ll(pin_num, &suc);
+    if (!suc) return E_BAD_CONFIG;
+
+    if (pin_num < 8)
+        LL_GPIO_SetAFPin_0_7(port, ll_pin, af);
+    else
+        LL_GPIO_SetAFPin_8_15(port, ll_pin, af);
+
+    LL_GPIO_SetPinMode(port, ll_pin, LL_GPIO_MODE_ALTERNATE);
+
+    return E_SUCCESS;
+}
+
+error_t configure_sparse_pins(char port_name, uint16_t mask, GPIO_TypeDef **port_dest, uint32_t mode, uint32_t otype)
+{
+    bool suc = true;
+    GPIO_TypeDef *port = port2periph(port_name, &suc);
+    if (!suc) return E_BAD_CONFIG;
+
+    for (int i = 0; i < 16; i++) {
+        if (mask & (1<<i)) {
+            uint32_t ll_pin = pin2ll((uint8_t) i, &suc);
+            LL_GPIO_SetPinMode(port, ll_pin, mode);
+            LL_GPIO_SetPinOutputType(port, ll_pin, otype);
+            LL_GPIO_SetPinSpeed(port, ll_pin, LL_GPIO_SPEED_FREQ_HIGH);
+        }
+    }
+
+    if (port_dest != NULL) {
+        *port_dest = port;
+    }
+
+    return E_SUCCESS;
+}
diff --git a/platform/pin_utils.h b/platform/pin_utils.h
index a996cde..94c83a5 100644
--- a/platform/pin_utils.h
+++ b/platform/pin_utils.h
@@ -75,4 +75,7 @@ uint16_t port_pack(uint16_t spread, uint16_t mask);
  */
 void deinit_unit_pins(Unit *unit);
 
+error_t configure_gpio_alternate(char port_name, uint8_t pin_num, uint32_t af);
+error_t configure_sparse_pins(char port_name, uint16_t mask, GPIO_TypeDef **port_dest, uint32_t mode, uint32_t otype);
+
 #endif //GEX_PIN_UTILS_H
diff --git a/units/i2c/unit_i2c.c b/units/i2c/unit_i2c.c
index ba5060b..e101ec8 100644
--- a/units/i2c/unit_i2c.c
+++ b/units/i2c/unit_i2c.c
@@ -21,9 +21,9 @@ struct priv {
 
     I2C_TypeDef *periph;
 
-    GPIO_TypeDef *port;
-    uint32_t ll_pin_scl;
-    uint32_t ll_pin_sda;
+//    GPIO_TypeDef *port;
+//    uint32_t ll_pin_scl;
+//    uint32_t ll_pin_sda;
 };
 
 // ------------------------------------------------------------------------
@@ -40,6 +40,10 @@ static void UI2C_loadBinary(Unit *unit, PayloadParser *pp)
     priv->anf = pp_bool(pp);
     priv->dnf = pp_u8(pp);
     priv->speed = pp_u8(pp);
+
+    if (version >= 1) {
+        priv->remap = pp_u8(pp);
+    }
 }
 
 /** Write to a binary buffer for storing in Flash */
@@ -47,12 +51,13 @@ static void UI2C_writeBinary(Unit *unit, PayloadBuilder *pb)
 {
     struct priv *priv = unit->data;
 
-    pb_u8(pb, 0); // version
+    pb_u8(pb, 1); // version
 
     pb_u8(pb, priv->periph_num);
     pb_bool(pb, priv->anf);
     pb_u8(pb, priv->dnf);
     pb_u8(pb, priv->speed);
+    pb_u8(pb, priv->remap);
 }
 
 // ------------------------------------------------------------------------
@@ -229,32 +234,11 @@ static error_t UI2C_init(Unit *unit)
 #endif
 
     // first, we have to claim the pins
-    Resource r_sda = pin2resource(portname, pin_sda, &suc);
-    Resource r_scl = pin2resource(portname, pin_scl, &suc);
-    if (!suc) return E_BAD_CONFIG;
-
-    TRY(rsc_claim(unit, r_sda));
-    TRY(rsc_claim(unit, r_scl));
-
-    priv->port = port2periph(portname, &suc);
-    priv->ll_pin_scl = pin2ll(pin_scl, &suc);
-    priv->ll_pin_sda = pin2ll(pin_sda, &suc);
-    if (!suc) return E_BAD_CONFIG;
-
-    // configure AF
-    if (pin_scl < 8) LL_GPIO_SetAFPin_0_7(priv->port, priv->ll_pin_scl, af_i2c);
-    else LL_GPIO_SetAFPin_8_15(priv->port, priv->ll_pin_scl, af_i2c);
-
-    if (pin_sda < 8) LL_GPIO_SetAFPin_0_7(priv->port, priv->ll_pin_sda, af_i2c);
-    else LL_GPIO_SetAFPin_8_15(priv->port, priv->ll_pin_sda, af_i2c);
-
-    LL_GPIO_SetPinMode(priv->port, priv->ll_pin_scl, LL_GPIO_MODE_ALTERNATE);
-    LL_GPIO_SetPinMode(priv->port, priv->ll_pin_sda, LL_GPIO_MODE_ALTERNATE);
-
-    // set as OpenDrain (this may not be needed - TODO check)
-    LL_GPIO_SetPinOutputType(priv->port, priv->ll_pin_scl, LL_GPIO_OUTPUT_OPENDRAIN);
-    LL_GPIO_SetPinOutputType(priv->port, priv->ll_pin_sda, LL_GPIO_OUTPUT_OPENDRAIN);
+    TRY(rsc_claim_pin(unit, portname, pin_sda));
+    TRY(rsc_claim_pin(unit, portname, pin_scl));
 
+    configure_gpio_alternate(portname, pin_sda, af_i2c);
+    configure_gpio_alternate(portname, pin_scl, af_i2c);
 
     if (priv->periph_num == 1) {
         __HAL_RCC_I2C1_CLK_ENABLE();
@@ -265,8 +249,7 @@ static error_t UI2C_init(Unit *unit)
     /* Disable the selected I2Cx Peripheral */
     LL_I2C_Disable(priv->periph);
     LL_I2C_ConfigFilters(priv->periph,
-                         priv->anf ? LL_I2C_ANALOGFILTER_ENABLE
-                                   : LL_I2C_ANALOGFILTER_DISABLE,
+                         (priv->anf ? LL_I2C_ANALOGFILTER_ENABLE : LL_I2C_ANALOGFILTER_DISABLE),
                          priv->dnf);
 
     LL_I2C_SetTiming(priv->periph, timing);
diff --git a/units/spi/unit_spi.c b/units/spi/unit_spi.c
index a315d50..d0b4b02 100644
--- a/units/spi/unit_spi.c
+++ b/units/spi/unit_spi.c
@@ -25,12 +25,7 @@ struct priv {
     uint16_t ssn_pins;  //!< SSN pin mask
 
     SPI_TypeDef *periph;
-
     GPIO_TypeDef *ssn_port;
-    GPIO_TypeDef *spi_port;
-    uint32_t ll_pin_miso;
-    uint32_t ll_pin_mosi;
-    uint32_t ll_pin_sck;
 };
 
 // ------------------------------------------------------------------------
@@ -291,34 +286,13 @@ static error_t USPI_init(Unit *unit)
 #endif
 
     // first, we have to claim the pins
-    Resource r_mosi = pin2resource(spi_portname, pin_mosi, &suc);
-    Resource r_miso = pin2resource(spi_portname, pin_miso, &suc);
-    Resource r_sck = pin2resource(spi_portname, pin_sck, &suc);
-    if (!suc) return E_BAD_CONFIG;
-
-    TRY(rsc_claim(unit, r_mosi));
-    TRY(rsc_claim(unit, r_miso));
-    TRY(rsc_claim(unit, r_sck));
-
-    priv->spi_port = port2periph(spi_portname, &suc);
-    priv->ll_pin_mosi = pin2ll(pin_mosi, &suc);
-    priv->ll_pin_miso = pin2ll(pin_miso, &suc);
-    priv->ll_pin_sck = pin2ll(pin_sck, &suc);
-    if (!suc) return E_BAD_CONFIG;
-
-    // configure AF
-    if (pin_mosi < 8) LL_GPIO_SetAFPin_0_7(priv->spi_port, priv->ll_pin_mosi, af_spi);
-    else LL_GPIO_SetAFPin_8_15(priv->spi_port, priv->ll_pin_mosi, af_spi);
+    TRY(rsc_claim_pin(unit, spi_portname, pin_mosi));
+    TRY(rsc_claim_pin(unit, spi_portname, pin_miso));
+    TRY(rsc_claim_pin(unit, spi_portname, pin_sck));
 
-    if (pin_miso < 8) LL_GPIO_SetAFPin_0_7(priv->spi_port, priv->ll_pin_miso, af_spi);
-    else LL_GPIO_SetAFPin_8_15(priv->spi_port, priv->ll_pin_miso, af_spi);
-
-    if (pin_sck < 8) LL_GPIO_SetAFPin_0_7(priv->spi_port, priv->ll_pin_sck, af_spi);
-    else LL_GPIO_SetAFPin_8_15(priv->spi_port, priv->ll_pin_sck, af_spi);
-
-    LL_GPIO_SetPinMode(priv->spi_port, priv->ll_pin_mosi, LL_GPIO_MODE_ALTERNATE);
-    LL_GPIO_SetPinMode(priv->spi_port, priv->ll_pin_miso, LL_GPIO_MODE_ALTERNATE);
-    LL_GPIO_SetPinMode(priv->spi_port, priv->ll_pin_sck, LL_GPIO_MODE_ALTERNATE);
+    configure_gpio_alternate(spi_portname, pin_mosi, af_spi);
+    configure_gpio_alternate(spi_portname, pin_miso, af_spi);
+    configure_gpio_alternate(spi_portname, pin_sck, af_spi);
 
     if (priv->periph_num == 1) {
         __HAL_RCC_SPI1_CLK_ENABLE();
@@ -328,22 +302,10 @@ static error_t USPI_init(Unit *unit)
 
     // configure SSN GPIOs
     {
-        priv->ssn_port = port2periph(priv->ssn_port_name, &suc);
-        if (!suc) return E_BAD_CONFIG;
-
         // Claim all needed pins
         TRY(rsc_claim_gpios(unit, priv->ssn_port_name, priv->ssn_pins));
-
-        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);
-                LL_GPIO_SetPinMode(priv->ssn_port, ll_pin, LL_GPIO_MODE_OUTPUT);
-                LL_GPIO_SetPinOutputType(priv->ssn_port, ll_pin, LL_GPIO_OUTPUT_PUSHPULL);
-                LL_GPIO_SetPinSpeed(priv->ssn_port, ll_pin, LL_GPIO_SPEED_FREQ_HIGH);
-            }
-        }
-
+        TRY(configure_sparse_pins(priv->ssn_port_name, priv->ssn_pins, &priv->ssn_port,
+                                  LL_GPIO_MODE_OUTPUT, LL_GPIO_OUTPUT_PUSHPULL));
         // Set the initial state - all high
         priv->ssn_port->ODR &= priv->ssn_pins;
     }
@@ -359,21 +321,10 @@ static error_t USPI_init(Unit *unit)
         dbg("Presc is %d", (int) presc);
         LL_SPI_SetBaudRatePrescaler(priv->periph, presc);
 
-        LL_SPI_SetClockPolarity(priv->periph, priv->cpol ?
-                                              LL_SPI_POLARITY_HIGH :
-                                              LL_SPI_POLARITY_LOW);
-
-        LL_SPI_SetClockPhase(priv->periph, priv->cpha ?
-                                           LL_SPI_PHASE_1EDGE :
-                                           LL_SPI_PHASE_2EDGE);
-
-        LL_SPI_SetTransferDirection(priv->periph, priv->tx_only ?
-                                                  LL_SPI_HALF_DUPLEX_TX :
-                                                  LL_SPI_FULL_DUPLEX);
-
-        LL_SPI_SetTransferBitOrder(priv->periph, priv->lsb_first ?
-                                                 LL_SPI_LSB_FIRST :
-                                                 LL_SPI_MSB_FIRST);
+        LL_SPI_SetClockPolarity(priv->periph,     priv->cpol ? LL_SPI_POLARITY_HIGH : LL_SPI_POLARITY_LOW);
+        LL_SPI_SetClockPhase(priv->periph,        priv->cpha ? LL_SPI_PHASE_1EDGE : LL_SPI_PHASE_2EDGE);
+        LL_SPI_SetTransferDirection(priv->periph, priv->tx_only ? LL_SPI_HALF_DUPLEX_TX : LL_SPI_FULL_DUPLEX);
+        LL_SPI_SetTransferBitOrder(priv->periph,  priv->lsb_first ? LL_SPI_LSB_FIRST : LL_SPI_MSB_FIRST);
 
         // TODO data size?