diff --git a/src/mame/drivers/psikyo.cpp b/src/mame/drivers/psikyo.cpp
index 1813c68a67b..c3bd9441fec 100644
--- a/src/mame/drivers/psikyo.cpp
+++ b/src/mame/drivers/psikyo.cpp
@@ -285,7 +285,7 @@ WRITE32_MEMBER(psikyo_state::s1945bl_oki_w)
 	{
 		// not at all sure about this, it seems to write 0 too often
 		uint8_t bank = (data & 0x00ff0000) >> 16;
-		if (bank < 4)
+		if (bank < 5)
 			m_okibank->set_entry(bank);
 	}
 
@@ -1962,7 +1962,7 @@ void psikyo_state::init_s1945bl()
 {
 	m_ka302c_banking = 1;
 
-	m_okibank->configure_entries(0, 4, memregion("oki")->base() + 0x30000, 0x10000);
+	m_okibank->configure_entries(0, 5, memregion("oki")->base() + 0x30000, 0x10000);
 	m_okibank->set_entry(0);
 }