diff --git a/include/apple2.mem.h b/include/apple2.mem.h
index 89c8741..e103734 100644
--- a/include/apple2.mem.h
+++ b/include/apple2.mem.h
@@ -56,7 +56,12 @@
 #define APPLE2_AUX_SIZE 0x10000
 
 /*
- * This is the base address (or offset) for all bank-switched memory
+ * This is the base address for system / internal ROM.
+ */
+#define APPLE2_SYSROM_OFFSET 0xC000
+
+/*
+ * This defines the base address for bank-switchable memory
  */
 #define APPLE2_BANK_OFFSET 0xD000
 
diff --git a/src/apple2.bank.c b/src/apple2.bank.c
index f85fbfb..93e8f29 100644
--- a/src/apple2.bank.c
+++ b/src/apple2.bank.c
@@ -52,7 +52,7 @@ SEGMENT_READER(apple2_bank_read)
     if (~mach->bank_switch & BANK_RAM) {
         // We need to account for the difference in address location
         // before we can successfully get any data from ROM.
-        return vm_segment_get(mach->rom, addr - APPLE2_BANK_OFFSET);
+        return vm_segment_get(mach->rom, addr - APPLE2_SYSROM_OFFSET);
     }
 
     // Each memory bank (main or auxiliary) have an additional 4k of RAM
diff --git a/tests/apple2.bank.c b/tests/apple2.bank.c
index d76ae16..78a62ee 100644
--- a/tests/apple2.bank.c
+++ b/tests/apple2.bank.c
@@ -65,8 +65,8 @@ Test(apple2_bank, read)
     // when addressing from main memory
     apple2_set_bank_switch(mach, BANK_WRITE);
     val = 123;
-    vm_segment_set(mach->rom, 0x77, val);
-    val = vm_segment_get(mach->rom, 0x77);
+    vm_segment_set(mach->rom, 0x1077, val);
+    val = vm_segment_get(mach->rom, 0x1077);
     cr_assert_eq(vm_segment_get(mach->main, 0xD077), val);
 
     // In RAM1 bank mode, setting a value in memory should return thaty
@@ -104,9 +104,9 @@ Test(apple2_bank, write)
     // were).
     right = 123;
     wrong = 222;
-    vm_segment_set(mach->rom, 0x77, right);
+    vm_segment_set(mach->rom, 0x1077, right);
     vm_segment_set(mach->main, 0xD077, wrong);
-    cr_assert_eq(vm_segment_get(mach->rom, 0x77), right);
+    cr_assert_eq(vm_segment_get(mach->rom, 0x1077), right);
     cr_assert_eq(vm_segment_get(mach->main, 0xD077), right);
 
     // RAM1 is the main bank; it's all 64k RAM in one chunk.
diff --git a/tests/apple2.c b/tests/apple2.c
index a7dcd0c..1ad6329 100644
--- a/tests/apple2.c
+++ b/tests/apple2.c
@@ -141,8 +141,8 @@ Test(apple2, set_bank_switch)
 
 Test(apple2, reset)
 {
-    vm_segment_set(mach->rom, 0x2FFC, 0x34);
-    vm_segment_set(mach->rom, 0x2FFD, 0x12);
+    vm_segment_set(mach->rom, 0x3FFC, 0x34);
+    vm_segment_set(mach->rom, 0x3FFD, 0x12);
     apple2_reset(mach);
 
     cr_assert_eq(mach->cpu->PC, 0x1234);