diff --git a/cpu/sam0_common/periph/eth.c b/cpu/sam0_common/periph/eth.c
index 7d1af599fe4fa..812505db2187c 100644
--- a/cpu/sam0_common/periph/eth.c
+++ b/cpu/sam0_common/periph/eth.c
@@ -246,7 +246,7 @@ int sam0_eth_send(const struct iolist *iolist)
             tx_curr->status |= DESC_TX_STATUS_WRAP;
             tx_idx = 0;
         }
-        __DSB();
+        __DMB();
         /* Start transmission */
         GMAC->NCR.reg |= GMAC_NCR_TSTART;
         /* Set the next buffer */
@@ -258,6 +258,12 @@ int sam0_eth_send(const struct iolist *iolist)
     return len;
 }
 
+unsigned _sam0_eth_get_last_len(void)
+{
+    unsigned idx = tx_idx ? tx_idx - 1 : ETH_TX_BUFFER_COUNT - 1;
+    return tx_desc[idx].status & DESC_TX_STATUS_LEN_MASK;
+}
+
 static int _try_receive(char* data, unsigned max_len, int block)
 {
     (void)block;
@@ -386,7 +392,8 @@ int sam0_eth_init(void)
     GMAC->RSR.reg = GMAC_RSR_HNO | GMAC_RSR_RXOVR | GMAC_RSR_REC | GMAC_RSR_BNA;
     GMAC->TSR.reg = 0xFFFF;
     /* Enable needed interrupts */
-    GMAC->IER.reg = GMAC_IER_RCOMP | GMAC_IER_TCOMP;
+    GMAC->IER.reg = GMAC_IER_RCOMP
+                  | GMAC_IER_TCOMP | GMAC_IER_TFC | GMAC_IER_RLEX;
 
     GMAC->NCFGR.reg = GMAC_NCFGR_MTIHEN
                     | GMAC_NCFGR_RXCOEN | GMAC_NCFGR_MAXFS | GMAC_NCFGR_CAF
diff --git a/cpu/sam0_common/sam0_eth/eth-netdev.c b/cpu/sam0_common/sam0_eth/eth-netdev.c
index 9571339233088..3b1ce6166a047 100644
--- a/cpu/sam0_common/sam0_eth/eth-netdev.c
+++ b/cpu/sam0_common/sam0_eth/eth-netdev.c
@@ -226,12 +226,13 @@ static int _sam0_eth_confirm_send(netdev_t *netdev, void *info)
         return -EBUSY;
     }
 
-    /* Transmit Frame Corruption, Collision Occurred, Transmit Underrun */
-    if (tsr & (GMAC_TSR_TFC | GMAC_TSR_COL | GMAC_TSR_UND)) {
+    /* Transmit Frame Corruption, Collision Occurred */
+    if (tsr & (GMAC_TSR_TFC | GMAC_TSR_COL)) {
         return -EIO;
     }
 
-    return 1;
+    extern unsigned _sam0_eth_get_last_len(void);
+    return _sam0_eth_get_last_len();
 }
 
 static int _sam0_eth_get(netdev_t *netdev, netopt_t opt, void *val, size_t max_len)