diff --git a/src/mame/drivers/vixen.cpp b/src/mame/drivers/vixen.cpp
index d3c77194da5..d600fa0100b 100644
--- a/src/mame/drivers/vixen.cpp
+++ b/src/mame/drivers/vixen.cpp
@@ -75,13 +75,19 @@ void vixen_state::update_interrupt()
 
 READ8_MEMBER( vixen_state::opram_r )
 {
-	membank("bank3")->set_entry(0); // read videoram
-	return m_program->read_byte(offset);
+	if (!space.debugger_access())
+		membank("bank3")->set_entry(0); // read videoram
+	bool const prev_debugger_access(m_program->debugger_access());
+	m_program->set_debugger_access(space.debugger_access());
+	UINT8 const data(m_program->read_byte(offset));
+	m_program->set_debugger_access(prev_debugger_access);
+	return data;
 }
 
 READ8_MEMBER( vixen_state::oprom_r )
 {
-	membank("bank3")->set_entry(1); // read rom
+	if (!space.debugger_access())
+		membank("bank3")->set_entry(1); // read rom
 	return m_rom[offset];
 }
 
diff --git a/src/mame/machine/osborne1.cpp b/src/mame/machine/osborne1.cpp
index 1db3c9abf61..7fc4029677b 100644
--- a/src/mame/machine/osborne1.cpp
+++ b/src/mame/machine/osborne1.cpp
@@ -116,7 +116,12 @@ READ8_MEMBER( osborne1_state::opcode_r )
 	}
 
 	// Now that's sorted out we can call the normal read handler
-	return m_maincpu->space(AS_PROGRAM).read_byte(offset);
+	address_space &program_space(m_maincpu->space(AS_PROGRAM));
+	bool const prev_debugger_access(program_space.debugger_access());
+	program_space.set_debugger_access(space.debugger_access());
+	UINT8 const data(program_space.read_byte(offset));
+	program_space.set_debugger_access(prev_debugger_access);
+	return data;
 }
 
 WRITE8_MEMBER( osborne1_state::bankswitch_w )