diff --git a/src/devices/cpu/z8/z8.cpp b/src/devices/cpu/z8/z8.cpp
index 4f93091f802..adf82562f04 100644
--- a/src/devices/cpu/z8/z8.cpp
+++ b/src/devices/cpu/z8/z8.cpp
@@ -29,6 +29,7 @@
 #define LOG_TIMER       (1U << 1)
 #define LOG_RECEIVE     (1U << 2)
 #define LOG_TRANSMIT    (1U << 3)
+#define LOG_IRQ         (1U << 4)
 
 #define VERBOSE 0
 #include "logmacro.h"
@@ -1331,7 +1332,10 @@ void z8_device::request_interrupt(int irq)
 	assert(irq >= 0 && irq < 6);
 
 	if (m_irq_initialized)
+	{
 		m_irq |= 1 << irq;
+		LOGMASKED(LOG_IRQ, "%s: IRQ%d requested\n", machine().time().to_string(), irq);
+	}
 }
 
 void z8_device::take_interrupt(int irq)
diff --git a/src/devices/cpu/z8/z8ops.hxx b/src/devices/cpu/z8/z8ops.hxx
index 22934842657..e49b54ac8e5 100644
--- a/src/devices/cpu/z8/z8ops.hxx
+++ b/src/devices/cpu/z8/z8ops.hxx
@@ -777,7 +777,7 @@ INSTRUCTION( swap_IR1 )         { mode_IR1(swap) }
 
 INSTRUCTION( ccf )              { m_flags ^= Z8_FLAGS_C; }
 INSTRUCTION( di )               { m_imr &= ~Z8_IMR_ENABLE; }
-INSTRUCTION( ei )               { m_imr |= Z8_IMR_ENABLE; m_irq_initialized = true; }
+INSTRUCTION( ei )               { m_imr |= Z8_IMR_ENABLE; if (!m_irq_initialized) LOGMASKED(LOG_IRQ, "(%04X): IRQs first enabled\n", m_ppc); m_irq_initialized = true; }
 INSTRUCTION( nop )              { /* no operation */ }
 INSTRUCTION( rcf )              { set_flag_c(0); }
 INSTRUCTION( scf )              { set_flag_c(1); }