diff --git a/src/board/system76/common/flash/main.c b/src/board/system76/common/flash/main.c
index 58d0d6986..be84a864c 100644
--- a/src/board/system76/common/flash/main.c
+++ b/src/board/system76/common/flash/main.c
@@ -48,8 +48,8 @@ void flash_write_enable(void);
  */
 void flash_entry(uint32_t addr, uint8_t *data, uint32_t length,
                  uint8_t command) __reentrant __critical {
-    // Only allow access from 64KB to 128KB.
-    if ((addr < 0x10000) || (length > 0x10000) || ((addr + length) > 0x20000))
+    // Only allow access from 64 KiB to the end of flash.
+    if ((addr < 0x10000) || (length > 0x10000) || ((addr + length) > CONFIG_EC_FLASH_SIZE))
         return;
 
     if (command == FLASH_COMMAND_READ) {
diff --git a/src/board/system76/common/keymap.c b/src/board/system76/common/keymap.c
index 9fbc3db82..228388d8e 100644
--- a/src/board/system76/common/keymap.c
+++ b/src/board/system76/common/keymap.c
@@ -8,7 +8,7 @@ bool keymap_fnlock = false;
 uint16_t __xdata DYNAMIC_KEYMAP[KM_LAY][KM_OUT][KM_IN];
 
 // Config is in the last sector of flash
-const uint32_t CONFIG_ADDR = 0x1FC00;
+const uint32_t CONFIG_ADDR = CONFIG_EC_FLASH_SIZE - 1024;
 // Signature is the size of the keymap
 const uint16_t CONFIG_SIGNATURE = sizeof(DYNAMIC_KEYMAP);
 
diff --git a/src/ec/ite/ec.mk b/src/ec/ite/ec.mk
index d61fa25ef..ce6b20411 100644
--- a/src/ec/ite/ec.mk
+++ b/src/ec/ite/ec.mk
@@ -45,3 +45,5 @@ CONFIG_EC_FLASH_SIZE = 262144
 else
 $(error flash size not specified)
 endif
+
+CFLAGS += -DCONFIG_EC_FLASH_SIZE=$(CONFIG_EC_FLASH_SIZE)