diff --git a/kernel/iec_listener.c b/kernel/iec_listener.c
index 810ae36..2314d33 100644
--- a/kernel/iec_listener.c
+++ b/kernel/iec_listener.c
@@ -108,16 +108,26 @@ static void emit_record(u8 kind, u8 value, u8 flags)
 
 /* --- busy-poll helper ---------------------------------------------------- */
 /*
- * Spin until CLK reaches `want_asserted`, or timeout/ATN/RESET. Caller holds
- * local IRQs disabled. Uses a microsecond budget rather than a fixed udelay so
- * a slightly-fast C64 is handled correctly (research §1.3).
+ * Spin until CLK reaches `want_asserted`, or timeout/ATN-change/RESET. Caller
+ * holds local IRQs disabled. Uses a microsecond budget rather than a fixed
+ * udelay so a slightly-fast C64 is handled correctly (research §1.3).
+ *
+ * The ATN abort is phase-relative, and IEC_RX_ATN means "ATN changed, abort":
+ *   - data_phase: ATN is released; abort if it ASSERTS (C64 interrupts data
+ *     transfer with a new command).
+ *   - command phase: ATN is asserted for the whole command byte; abort if it
+ *     RELEASES (the command sequence is over -> hand back to the state machine).
+ * Treating any asserted ATN as an abort (the previous behaviour) made command
+ * reception impossible: ATN is legitimately low the entire command phase, so
+ * the very first poll aborted before a single bit was clocked.
  */
-static enum iec_rx wait_clk(bool want_asserted, unsigned int timeout_us)
+static enum iec_rx wait_clk(bool want_asserted, unsigned int timeout_us,
+			    bool data_phase)
 {
 	unsigned int waited = 0;
 
 	while (iec_clk_asserted() != want_asserted) {
-		if (iec_atn_asserted())
+		if (iec_atn_asserted() == data_phase)
 			return IEC_RX_ATN;
 		if (iec_reset_asserted())
 			return IEC_RX_RESET;
@@ -143,7 +153,7 @@ static enum iec_rx receive_byte(u8 *out, bool *eoi, bool data_phase)
 	*eoi = false;
 
 	/* 1. READY-FOR-DATA: wait for talker to release CLK, then release DATA */
-	rc = wait_clk(false /* released */, IEC_CLK_TIMEOUT_US);
+	rc = wait_clk(false /* released */, IEC_CLK_TIMEOUT_US, data_phase);
 	if (rc != IEC_RX_OK)
 		return rc;
 	iec_data_release();
@@ -171,10 +181,12 @@ static enum iec_rx receive_byte(u8 *out, bool *eoi, bool data_phase)
 
 	/* 3. RECEIVE 8 BITS, LSB first */
 	for (i = 0; i < 8; i++) {
-		rc = wait_clk(true /* asserted: data invalid/setup */, IEC_CLK_TIMEOUT_US);
+		rc = wait_clk(true /* asserted: data invalid/setup */,
+			      IEC_CLK_TIMEOUT_US, data_phase);
 		if (rc != IEC_RX_OK)
 			goto out;
-		rc = wait_clk(false /* released: data valid -> sample */, IEC_CLK_TIMEOUT_US);
+		rc = wait_clk(false /* released: data valid -> sample */,
+			      IEC_CLK_TIMEOUT_US, data_phase);
 		if (rc != IEC_RX_OK)
 			goto out;
 		/* released(high) = bit 1, asserted(low) = bit 0 */