diff --git a/hw/application_fpga/fw/tk1/main.c b/hw/application_fpga/fw/tk1/main.c
index 902ba37..8bcaef4 100644
--- a/hw/application_fpga/fw/tk1/main.c
+++ b/hw/application_fpga/fw/tk1/main.c
@@ -197,7 +197,7 @@ int main()
 			// clang-format off
 			asm volatile(
 				"li a0, 0xd0000000;" // FW_RAM
-				"li a1, 0xd0000400;" // End of FW_RAM
+				"li a1, 0xd0000800;" // End of 2 KB FW_RAM (just past the end)
 				"loop:;"
 				"sw zero, 0(a0);"
 				"addi a0, a0, 4;"
diff --git a/hw/application_fpga/fw/tk1/start.S b/hw/application_fpga/fw/tk1/start.S
index 5362a77..7cd169d 100644
--- a/hw/application_fpga/fw/tk1/start.S
+++ b/hw/application_fpga/fw/tk1/start.S
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2022 - Tillitis AB
+ * Copyright (C) 2022, 2023 - Tillitis AB
  * SPDX-License-Identifier: GPL-2.0-only
 */
 
@@ -49,7 +49,7 @@ clear:
         /*
          * Init stack at top of fw_ram. Leave 16 byte for entering our first function
          */
-        li sp, 0xd00003f0 // 1 kiB - 16 byte in FW_RAM
+        li sp, 0xd00007f0 // 2 kiB (TK1_MMIO_FW_RAM_SIZE) minus 16 byte
 
 	call main