diff --git a/part10-multicore/fb.c b/part10-multicore/fb.c
index 43fae91..b3e3f0d 100644
--- a/part10-multicore/fb.c
+++ b/part10-multicore/fb.c
@@ -15,7 +15,7 @@ void fb_init()
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)
 
diff --git a/part11-breakout-smp/lib/fb.c b/part11-breakout-smp/lib/fb.c
index 7fc4f24..0daa0fe 100644
--- a/part11-breakout-smp/lib/fb.c
+++ b/part11-breakout-smp/lib/fb.c
@@ -17,7 +17,7 @@ void fb_init()
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)
 
diff --git a/part12-wgt/wgt/wsetmode.c b/part12-wgt/wgt/wsetmode.c
index 7973519..df0cdfc 100644
--- a/part12-wgt/wgt/wsetmode.c
+++ b/part12-wgt/wgt/wsetmode.c
@@ -7,7 +7,7 @@ void vga256(void)
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)
 
diff --git a/part13-interrupts/lib/fb.c b/part13-interrupts/lib/fb.c
index 80ef496..2cc89f7 100644
--- a/part13-interrupts/lib/fb.c
+++ b/part13-interrupts/lib/fb.c
@@ -15,7 +15,7 @@ void fb_init()
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)
 
diff --git a/part14-ethernet/kernel/arp.c b/part14-ethernet/kernel/arp.c
index 8cb2a94..3151d64 100644
--- a/part14-ethernet/kernel/arp.c
+++ b/part14-ethernet/kernel/arp.c
@@ -1,6 +1,8 @@
 #include "../net/enc28j60.h"
 #include "../include/fb.h"
 
+ENC_HandleTypeDef handle;
+
 // Structure for Ethernet header
 
 typedef struct {
@@ -11,8 +13,8 @@ typedef struct {
 
 // Ethernet packet types
 
-#define ARPPACKET 0x0806
-#define IPPACKET  0x0800
+#define ARPPACKET 0x0608
+#define IPPACKET  0x0008
 
 // Structure for an ARP Packet
 
@@ -31,12 +33,12 @@ typedef struct {
 
 // ARP OpCodes
 
-#define ARPREPLY   0x0002
-#define ARPREQUEST 0x0001
+#define ARPREPLY   0x0200
+#define ARPREQUEST 0x0100
 
 // ARP hardware types
 
-#define ETHERNET 0x0001
+#define ETHERNET   0x0100
 
 // MAC address to be assigned to the ENC28J60
 
@@ -135,60 +137,67 @@ void SendArpPacket(uint8_t *targetIP, uint8_t *deviceMAC)
    }
 
    // Send the packet
-   ENC_WriteBuffer((unsigned char*)&arpPacket, sizeof(ARP));
+
+   if (ENC_RestoreTXBuffer(&handle, sizeof(ARP)) == 0) {
+      debugstr("Sending ARP request... ");
+      debugcrlf();
+      
+      ENC_WriteBuffer((unsigned char *)&arpPacket, sizeof(ARP));
+      handle.transmitLength = sizeof(ARP);
+      ENC_Transmit(&handle);
+   }
 }
 
 void arp_test(void)
 {
-   unsigned int tries = 0;
-   ARP checkPacket;
-
-   debugstr("Sending ARP request... ");
+   ARP *checkPacket;
 
    SendArpPacket(routerIP, myMAC);
 
-   debugstr("done.");
-   debugcrlf();
-
    debugstr("Waiting for ARP response... ");
    debugcrlf();
 
-   while (tries < 1000) {
-      if (ENC_ReadBuffer((unsigned char *)&checkPacket, sizeof(ARP)) == 0) {
+   while (1) {
+      if (!ENC_GetReceivedFrame(&handle)) {
          continue;
       }
-      if (!memcmp(checkPacket.senderIP, routerIP, 4)) {
-         // Success! We have found our router's MAC address
 
-         memcpy(routerMAC, checkPacket.senderMAC, 6);
-         debugstr("Router MAC is ");
-         debughex(routerMAC[0]);
-         debughex(routerMAC[1]);
-         debughex(routerMAC[2]);
-         debughex(routerMAC[3]);
-         debughex(routerMAC[4]);
-         debughex(routerMAC[5]);
-         debugcrlf();
+      uint16_t len    = handle.RxFrameInfos.length;
+      uint8_t *buffer = (uint8_t *)handle.RxFrameInfos.buffer;
+      checkPacket     = (ARP *)buffer;
+
+      if (len > 0) {
+         if (!memcmp(checkPacket->senderIP, routerIP, 4)) {
+            // Success! We have found our router's MAC address
+
+            memcpy(routerMAC, checkPacket->senderMAC, 6);
+            debugstr("Router MAC is ");
+            debughex(routerMAC[0]);
+            debughex(routerMAC[1]);
+            debughex(routerMAC[2]);
+            debughex(routerMAC[3]);
+            debughex(routerMAC[4]);
+            debughex(routerMAC[5]);
+            debugcrlf();
+
+            break;
+         }
       }
-      tries++;
    }
-
-   debugstr("Timed out.");
-   debugcrlf();
 }
 
 void init_network(void)
 {
-   ENC_HandleTypeDef handle;
-
-   debugstr("Setting MAC address to C0:FF:EE:C0:FF:EE.");
-   debugcrlf();
-
    handle.Init.DuplexMode = ETH_MODE_FULLDUPLEX;
    handle.Init.MACAddr = myMAC;
    handle.Init.ChecksumMode = ETH_CHECKSUM_BY_HARDWARE;
    handle.Init.InterruptEnableBits = 0;
 
+   debugstr("Setting MAC address to C0:FF:EE:C0:FF:EE.");
+   debugcrlf();
+
+   ENC_SetMacAddr(&handle);
+
    debugstr("Starting network up.");
    debugcrlf();
 
diff --git a/part14-ethernet/kernel/kernel.c b/part14-ethernet/kernel/kernel.c
index e0b4a0d..800add3 100644
--- a/part14-ethernet/kernel/kernel.c
+++ b/part14-ethernet/kernel/kernel.c
@@ -8,10 +8,10 @@
 void initProgress(void)
 {
     drawRect(0, 0, 301, 50, 0x0f, 0);
-    drawString(309, 21, "Core 1", 0x0f, 1);
+    drawString(309, 21, "Core 0", 0x0f, 1);
 
     drawRect(0, 60, 301, 110, 0x0f, 0);
-    drawString(309, 81, "Core 2", 0x0f, 1);
+    drawString(309, 81, "Core 1", 0x0f, 1);
 
     drawRect(0, 120, 301, 170, 0x0f, 0);
     drawString(309, 141, "Timer 1", 0x0f, 1);
@@ -28,28 +28,32 @@ void drawProgress(unsigned int core, unsigned int val) {
     if (val > 0) drawRect(1, (60 * core) + 1, (val * 3), (60 * core) + 49, col, 1);
 }
 
-unsigned int c2_done = 0;
+void core3_main(void) {
+    clear_core3();                // Only run once
 
-void core2_main(void)
-{
-    unsigned int core2_val = 0;
+    // Test the network card
 
-    clear_core2();                // Only run once
-
-    while (core2_val <= 100) {
-       wait_msec(0x100000);
-       drawProgress(1, core2_val);
-       core2_val++;
-    }
-
-    debugstr("Core 2 done.");
-    debugcrlf();
-
-    c2_done = 1;
+    spi_init();
+    init_network();
+    arp_test();
 
     while(1);
 }
 
+void core0_main(void)
+{
+    unsigned int core0_val = 0;
+
+    while (core0_val <= 100) {
+       wait_msec(0x100000);
+       drawProgress(0, core0_val);
+       core0_val++;
+    }
+
+    debugstr("Core 0 done.");
+    debugcrlf();
+}
+
 void core1_main(void)
 {
     unsigned int core1_val = 0;
@@ -58,7 +62,7 @@ void core1_main(void)
 
     while (core1_val <= 100) {
        wait_msec(0x3FFFF);
-       drawProgress(0, core1_val);
+       drawProgress(1, core1_val);
        core1_val++;
     }
 
@@ -144,10 +148,9 @@ void main(void)
 
     initProgress();
 
-    // Kick it off on core 1&2
+    // Kick it off on core 1
 
     start_core1(core1_main);
-    start_core2(core2_main);
 
     // Kick off the timers
 
@@ -156,18 +159,13 @@ void main(void)
     irq_enable();
     timer_init();
 
-    // Test the network card
+    // Kick it off on core 3
 
-    spi_init();
-    init_network();
-    arp_test();
+    start_core3(core3_main);
 
-    // The work is done - wait for timers to get done
+    // Kick it off on core 0
 
-    debugstr("Core 0 done.");
-    debugcrlf();
-
-    while (!c2_done);
+    core0_main();
 
     // Disable IRQs and loop endlessly
 
diff --git a/part14-ethernet/lib/fb.c b/part14-ethernet/lib/fb.c
index 80ef496..2cc89f7 100644
--- a/part14-ethernet/lib/fb.c
+++ b/part14-ethernet/lib/fb.c
@@ -15,7 +15,7 @@ void fb_init()
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)
 
diff --git a/part14-ethernet/net/enc28j60.c b/part14-ethernet/net/enc28j60.c
index 57189d3..4ce5d66 100644
--- a/part14-ethernet/net/enc28j60.c
+++ b/part14-ethernet/net/enc28j60.c
@@ -376,8 +376,7 @@ void enc_reset(ENC_HandleTypeDef *handle) {
    */
 
   handle->bank = 0; /* Initialize the trace on the current selected bank */
-  //up_mdelay(2);
-  HAL_Delay(2); /* >1000 µs, conforms to errata #2 */
+  up_udelay(2); /* >1000 µs, conforms to errata #2 */
 }
 
 /****************************************************************************
@@ -797,7 +796,7 @@ bool ENC_Start(ENC_HandleTypeDef *handle)
     enc_wrbreg(handle, ENC_ERXFCON, ERXFCON_UCEN | ERXFCON_CRCEN | ERXFCON_BCEN);
 
 	do {
-		HAL_Delay(10); /* Wait for 10 ms to let the clock be ready */
+		up_udelay(10); /* Wait for 10 ms to let the clock be ready */
 		regval = enc_rdbreg(handle, ENC_ESTAT);
 	} while ((regval & ESTAT_CLKRDY) == 0);
 
@@ -993,7 +992,7 @@ void ENC_WriteBuffer(void *buffer, uint16_t buflen)
 }
 
 /****************************************************************************
- * Function: ENC_ReadBuffer
+ * Function: enc_rdbuffer
  *
  * Description:
  *   Read a buffer of data.
@@ -1010,10 +1009,8 @@ void ENC_WriteBuffer(void *buffer, uint16_t buflen)
  *
  ****************************************************************************/
 
-uint8_t ENC_ReadBuffer(void *buffer, uint16_t buflen)
+static void enc_rdbuffer(void *buffer, uint16_t buflen)
 {
-  uint8_t read_count = 0;
-
   /* Select ENC28J60 chip */
 
   ENC_SPI_Select(true);
@@ -1024,11 +1021,9 @@ uint8_t ENC_ReadBuffer(void *buffer, uint16_t buflen)
 
   /* Then read the buffer data */
 
-  read_count = ENC_SPI_SendBuf(NULL, buffer, buflen);
+  ENC_SPI_SendBuf(NULL, buffer, buflen);
 
   /* De-select ENC28J60 chip: done in ENC_SPI_SendBuf callback */
-
-  return read_count;
 }
 
 /****************************************************************************
@@ -1153,6 +1148,8 @@ void ENC_Transmit(ENC_HandleTypeDef *handle)
     PT_BEGIN(pt);
 
     if (handle->transmitLength != 0) {
+        debugstr("We're actually sending"); debugcrlf();
+
         /* A frame is ready for transmission */
         /* Set TXRTS to send the packet in the transmit buffer */
 
@@ -1191,7 +1188,7 @@ void ENC_Transmit(ENC_HandleTypeDef *handle)
                 enc_wrbreg(handle, ENC_ERDPTL, addtTsv4 & 0xff);
                 enc_wrbreg(handle, ENC_ERDPTH, addtTsv4 >> 8);
 
-                ENC_ReadBuffer(&tsv4, 1);
+                enc_rdbuffer(&tsv4, 1);
                 regval = enc_rdgreg(ENC_EIR);
                 if (!(regval & EIR_TXERIF) || !(tsv4 & TSV_LATECOL)) {
                     break;
@@ -1201,7 +1198,10 @@ void ENC_Transmit(ENC_HandleTypeDef *handle)
         } while (handle->retries > 0);
         /* Transmission finished (but can be unsuccessful) */
         handle->transmitLength = 0;
+    } else {
+        debugstr("Nothing to send"); debugcrlf();
     }
+    debugstr("We're done sending"); debugcrlf();
     PT_END(pt);
 }
 
@@ -1246,7 +1246,7 @@ bool ENC_GetReceivedFrame(ENC_HandleTypeDef *handle)
     * and wrap to the beginning of the read buffer as necessary)
     */
 
-    ENC_ReadBuffer(rsv, 6);
+    enc_rdbuffer(rsv, 6);
 
     /* Decode the new next packet pointer, and the RSV.  The
     * RSV is encoded as:
@@ -1285,7 +1285,7 @@ bool ENC_GetReceivedFrame(ENC_HandleTypeDef *handle)
             * end_rdbuffer (above).
             */
 
-            ENC_ReadBuffer(handle->RxFrameInfos.buffer, handle->RxFrameInfos.length);
+            enc_rdbuffer(handle->RxFrameInfos.buffer, handle->RxFrameInfos.length);
 
         }
     }
diff --git a/part14-ethernet/net/enc28j60.h b/part14-ethernet/net/enc28j60.h
index c34152a..2c692fd 100644
--- a/part14-ethernet/net/enc28j60.h
+++ b/part14-ethernet/net/enc28j60.h
@@ -686,7 +686,6 @@ int8_t ENC_RestoreTXBuffer(ENC_HandleTypeDef *handle, uint16_t len);
  ****************************************************************************/
 
 void ENC_WriteBuffer(void *buffer, uint16_t buflen);
-uint8_t ENC_ReadBuffer(void *buffer, uint16_t buflen);
 
 /****************************************************************************
  * Function: ENC_Transmit
diff --git a/part5-framebuffer/fb.c b/part5-framebuffer/fb.c
index 3b4450b..7b44d08 100644
--- a/part5-framebuffer/fb.c
+++ b/part5-framebuffer/fb.c
@@ -12,7 +12,7 @@ void fb_init()
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)
 
diff --git a/part6-breakout/fb.c b/part6-breakout/fb.c
index ff52a43..d607f7e 100644
--- a/part6-breakout/fb.c
+++ b/part6-breakout/fb.c
@@ -12,7 +12,7 @@ void fb_init()
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)
 
diff --git a/part7-bluetooth/fb.c b/part7-bluetooth/fb.c
index 43fae91..b3e3f0d 100644
--- a/part7-bluetooth/fb.c
+++ b/part7-bluetooth/fb.c
@@ -15,7 +15,7 @@ void fb_init()
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)
 
diff --git a/part8-breakout-ble/fb.c b/part8-breakout-ble/fb.c
index 55d944a..d6b9913 100644
--- a/part8-breakout-ble/fb.c
+++ b/part8-breakout-ble/fb.c
@@ -17,7 +17,7 @@ void fb_init()
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)
 
diff --git a/part9-sound/fb.c b/part9-sound/fb.c
index 43fae91..b3e3f0d 100644
--- a/part9-sound/fb.c
+++ b/part9-sound/fb.c
@@ -15,7 +15,7 @@ void fb_init()
 
     mbox[2] = MBOX_TAG_SETPHYWH; // Tag identifier
     mbox[3] = 8; // Value size in bytes
-    mbox[4] = 8; // Value size in bytes (again!)
+    mbox[4] = 0;
     mbox[5] = 1920; // Value(width)
     mbox[6] = 1080; // Value(height)