diff --git a/.github/workflows/test-sim-self-update.yml b/.github/workflows/test-sim-self-update.yml
new file mode 100644
index 0000000000..a447f23508
--- /dev/null
+++ b/.github/workflows/test-sim-self-update.yml
@@ -0,0 +1,73 @@
+name: Simulator self-update test
+
+on:
+  push:
+    branches: [ 'master', 'main', 'release/**' ]
+  pull_request:
+    branches: [ '*' ]
+
+jobs:
+  self_update_simulator_test:
+    runs-on: ubuntu-latest
+    timeout-minutes: 15
+
+    steps:
+      - uses: actions/checkout@v4
+        with:
+          submodules: true
+
+      - name: Workaround for sources.list
+        run: |
+            # Replace sources
+
+            set -euxo pipefail
+
+            # Peek (what repos are active now)
+            apt-cache policy
+            grep -RInE '^(deb|Types|URIs)' /etc/apt || true
+
+            # Enable nullglob so *.list/*.sources that don't exist don't break sed
+            shopt -s nullglob
+
+            echo "Replace sources.list (legacy)"
+            sudo sed -i \
+              -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+              /etc/apt/sources.list || true
+
+            echo "Replace sources.list.d/*.list (legacy)"
+            for f in /etc/apt/sources.list.d/*.list; do
+              sudo sed -i \
+                -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+                "$f"
+            done
+
+            echo "Replace sources.list.d/*.sources (deb822)"
+            for f in /etc/apt/sources.list.d/*.sources; do
+              sudo sed -i \
+                -e "s|https\?://azure\.archive\.ubuntu\.com/ubuntu/?|http://mirror.arizona.edu/ubuntu/|g" \
+                -e "s|https\?://azure\.archive\.ubuntu\.com|http://mirror.arizona.edu|g" \
+                "$f"
+            done
+
+            echo "Fix /etc/apt/apt-mirrors.txt (used by URIs: mirror+file:...)"
+            if grep -qE '^[[:space:]]*https?://azure\.archive\.ubuntu\.com/ubuntu/?' /etc/apt/apt-mirrors.txt; then
+              # Replace azure with our mirror (idempotent)
+              sudo sed -i 's|https\?://azure\.archive\.ubuntu\.com/ubuntu/|http://mirror.arizona.edu/ubuntu/|g' /etc/apt/apt-mirrors.txt
+            fi
+
+            # Peek (verify changes)
+            grep -RIn "azure.archive.ubuntu.com" /etc/apt || true
+            grep -RInE '^(deb|Types|URIs)' /etc/apt || true
+            echo "--- apt-mirrors.txt ---"
+            cat /etc/apt/apt-mirrors.txt || true
+
+      - name: Run self-update test (internal flash)
+        run: |
+          cp config/examples/sim-self-update.config .config
+          make test-sim-self-update
+
+      - name: Run self-update test (external flash)
+        run: |
+          make clean
+          cp config/examples/sim-self-update-ext.config .config
+          make test-sim-self-update-ext
diff --git a/config/examples/sim-self-update-ext.config b/config/examples/sim-self-update-ext.config
new file mode 100644
index 0000000000..11bb1b00b8
--- /dev/null
+++ b/config/examples/sim-self-update-ext.config
@@ -0,0 +1,21 @@
+ARCH=sim
+TARGET=sim
+SIGN?=ED25519
+HASH?=SHA256
+WOLFBOOT_SMALL_STACK?=0
+SPI_FLASH=0
+EXT_FLASH=1
+DEBUG=1
+RAM_CODE=1
+WOLFBOOT_VERSION=1
+
+# sizes should be multiple of system page size
+WOLFBOOT_PARTITION_SIZE=0x40000
+WOLFBOOT_SECTOR_SIZE=0x1000
+WOLFBOOT_PARTITION_BOOT_ADDRESS=0x20000
+# Update and swap on external flash (address 0x00000)
+WOLFBOOT_PARTITION_UPDATE_ADDRESS=0x00000
+WOLFBOOT_PARTITION_SWAP_ADDRESS=0x40000
+
+# required for keytools
+WOLFBOOT_FIXED_PARTITIONS=1
diff --git a/config/examples/sim-self-update.config b/config/examples/sim-self-update.config
new file mode 100644
index 0000000000..13a0561848
--- /dev/null
+++ b/config/examples/sim-self-update.config
@@ -0,0 +1,19 @@
+ARCH=sim
+TARGET=sim
+SIGN?=ED25519
+HASH?=SHA256
+WOLFBOOT_SMALL_STACK?=0
+SPI_FLASH=0
+DEBUG=1
+RAM_CODE=1
+WOLFBOOT_VERSION=1
+
+# sizes should be multiple of system page size
+WOLFBOOT_PARTITION_SIZE=0x40000
+WOLFBOOT_SECTOR_SIZE=0x1000
+WOLFBOOT_PARTITION_BOOT_ADDRESS=0x80000
+WOLFBOOT_PARTITION_UPDATE_ADDRESS=0x100000
+WOLFBOOT_PARTITION_SWAP_ADDRESS=0x180000
+
+# required for keytools
+WOLFBOOT_FIXED_PARTITIONS=1
diff --git a/hal/sim.c b/hal/sim.c
index 4df7f8d524..58eb743f6f 100644
--- a/hal/sim.c
+++ b/hal/sim.c
@@ -596,6 +596,11 @@ int wolfBoot_dualboot_candidate(void)
 }
 #endif
 
+void arch_reboot(void)
+{
+    exit(0);
+}
+
 #ifdef WOLFBOOT_ENABLE_WOLFHSM_CLIENT
 
 int hal_hsm_init_connect(void)
diff --git a/src/update_flash.c b/src/update_flash.c
index ba720af7a5..b51f400a97 100644
--- a/src/update_flash.c
+++ b/src/update_flash.c
@@ -84,7 +84,13 @@ static void RAMFUNCTION wolfBoot_self_update(struct wolfBoot_image *src)
         while (pos < src->fw_size) {
             uint8_t buffer[FLASHBUFFER_SIZE];
             if (src_offset + pos < (src->fw_size + IMAGE_HEADER_SIZE + FLASHBUFFER_SIZE))  {
+#ifdef ARCH_SIM
+                /* Use ARCH_FLASH_OFFSET for simulator: flash is mmap'd at runtime,
+                 * so the linker symbol _start_text does not point to simulated flash */
+                uintptr_t opos = pos + ARCH_FLASH_OFFSET;
+#else
                 uintptr_t opos = pos + ((uintptr_t)&_start_text);
+#endif
                 ext_flash_check_read((uintptr_t)(src->hdr) + src_offset + pos, (void*)buffer, FLASHBUFFER_SIZE);
                 hal_flash_write(opos, buffer, FLASHBUFFER_SIZE);
             }
@@ -96,7 +102,13 @@ static void RAMFUNCTION wolfBoot_self_update(struct wolfBoot_image *src)
     while (pos < src->fw_size) {
         if (src_offset + pos < (src->fw_size + IMAGE_HEADER_SIZE + FLASHBUFFER_SIZE))  {
             uint8_t *orig = (uint8_t*)(src->hdr + src_offset + pos);
+#ifdef ARCH_SIM
+            /* Use ARCH_FLASH_OFFSET for simulator: flash is mmap'd at runtime,
+             * so the linker symbol _start_text does not point to simulated flash */
+            hal_flash_write(pos + ARCH_FLASH_OFFSET, orig, FLASHBUFFER_SIZE);
+#else
             hal_flash_write(pos + (uintptr_t)&_start_text, orig, FLASHBUFFER_SIZE);
+#endif
         }
         pos += FLASHBUFFER_SIZE;
     }
diff --git a/tools/test.mk b/tools/test.mk
index ac5bb95026..ff91bd80c9 100644
--- a/tools/test.mk
+++ b/tools/test.mk
@@ -240,6 +240,58 @@ test-sim-rollback-flash: wolfboot.elf test-sim-internal-flash-with-update FORCE
 	$(Q)(test `./wolfboot.elf success get_version` -eq 1)
 	$(Q)(test `./wolfboot.elf get_version` -eq 1)
 
+# Test bootloader self-update mechanism using simulator. Since simulator memmaps runtime addresses
+# the best we can do is ensure the self-update copies the intact self-update image to the expected location
+test-sim-self-update: wolfboot.bin FORCE
+	@echo "=== Simulator Self-Update Test ==="
+	@# Create dummy payload (0xAA pattern) and sign as wolfBoot update v2
+	$(Q)dd if=/dev/zero bs=$$(wc -c < wolfboot.bin | awk '{print $$1}') count=1 2>/dev/null | tr '\000' '\252' > dummy_update.bin
+	$(Q)$(SIGN_ENV) $(SIGN_TOOL) $(SIGN_OPTIONS) --wolfboot-update dummy_update.bin $(PRIVATE_KEY) 2
+	@# Create update partition with signed update and "pBOOT" trailer. Necessary since there is no running
+	@# app to trigger an initial update
+	$(Q)dd if=/dev/zero bs=$$(($(WOLFBOOT_PARTITION_SIZE))) count=1 2>/dev/null | tr '\000' '\377' > update_part.dd
+	$(Q)dd if=dummy_update_v2_signed.bin of=update_part.dd bs=1 conv=notrunc
+	$(Q)printf "pBOOT" | dd of=update_part.dd bs=1 seek=$$(($(WOLFBOOT_PARTITION_SIZE) - 5)) conv=notrunc
+	@# Create erased boot and swap partitions
+	$(Q)dd if=/dev/zero bs=$$(($(WOLFBOOT_PARTITION_SIZE))) count=1 2>/dev/null | tr '\000' '\377' > boot_part.dd
+	$(Q)dd if=/dev/zero bs=$$(($(WOLFBOOT_SECTOR_SIZE))) count=1 2>/dev/null | tr '\000' '\377' > erased_sec.dd
+	@# Assemble flash: wolfboot.bin at 0, empty boot partition, update partition, swap
+	$(Q)$(BINASSEMBLE) internal_flash.dd \
+		0 wolfboot.bin \
+		$$(($(WOLFBOOT_PARTITION_BOOT_ADDRESS) - $(ARCH_FLASH_OFFSET))) boot_part.dd \
+		$$(($(WOLFBOOT_PARTITION_UPDATE_ADDRESS) - $(ARCH_FLASH_OFFSET))) update_part.dd \
+		$$(($(WOLFBOOT_PARTITION_SWAP_ADDRESS) - $(ARCH_FLASH_OFFSET))) erased_sec.dd
+	@# Run simulator - self-update runs before app boot, writes dummy to offset 0, then reboots
+	$(Q)./wolfboot.elf get_version || true
+	@# Verify dummy payload was written to bootloader region, indicating the self update swapped images as expected
+	$(Q)cmp -n $$(wc -c < dummy_update.bin | awk '{print $$1}') dummy_update.bin internal_flash.dd && echo "=== Self-update test PASSED ==="
+
+# Test bootloader self-update mechanism with external flash
+test-sim-self-update-ext: wolfboot.bin FORCE
+	@echo "=== Simulator Self-Update Test (External Flash) ==="
+	@# Create dummy payload (0xAA pattern) and sign as wolfBoot update v2
+	$(Q)dd if=/dev/zero bs=$$(wc -c < wolfboot.bin | awk '{print $$1}') count=1 2>/dev/null | tr '\000' '\252' > dummy_update.bin
+	$(Q)$(SIGN_ENV) $(SIGN_TOOL) $(SIGN_OPTIONS) --wolfboot-update dummy_update.bin $(PRIVATE_KEY) 2
+	@# Create update partition with signed update and "pBOOT" trailer
+	$(Q)dd if=/dev/zero bs=$$(($(WOLFBOOT_PARTITION_SIZE))) count=1 2>/dev/null | tr '\000' '\377' > update_part.dd
+	$(Q)dd if=dummy_update_v2_signed.bin of=update_part.dd bs=1 conv=notrunc
+	$(Q)printf "pBOOT" | dd of=update_part.dd bs=1 seek=$$(($(WOLFBOOT_PARTITION_SIZE) - 5)) conv=notrunc
+	@# Create erased boot and swap partitions
+	$(Q)dd if=/dev/zero bs=$$(($(WOLFBOOT_PARTITION_SIZE))) count=1 2>/dev/null | tr '\000' '\377' > boot_part.dd
+	$(Q)dd if=/dev/zero bs=$$(($(WOLFBOOT_SECTOR_SIZE))) count=1 2>/dev/null | tr '\000' '\377' > erased_sec.dd
+	@# Assemble internal flash: wolfboot.bin at 0, empty boot partition
+	$(Q)$(BINASSEMBLE) internal_flash.dd \
+		0 wolfboot.bin \
+		$$(($(WOLFBOOT_PARTITION_BOOT_ADDRESS) - $(ARCH_FLASH_OFFSET))) boot_part.dd
+	@# Assemble external flash: update partition, swap sector
+	$(Q)$(BINASSEMBLE) external_flash.dd \
+		0 update_part.dd \
+		$(WOLFBOOT_PARTITION_SIZE) erased_sec.dd
+	@# Run simulator - self-update reads from external, writes to internal at offset 0
+	$(Q)./wolfboot.elf get_version || true
+	@# Verify dummy payload was written to bootloader region
+	$(Q)cmp -n $$(wc -c < dummy_update.bin | awk '{print $$1}') dummy_update.bin internal_flash.dd && echo "=== Self-update test (External Flash) PASSED ==="
+
 test-self-update: FORCE
 	@mv $(PRIVATE_KEY) private_key.old
 	@make clean factory.bin RAM_CODE=1 WOLFBOOT_VERSION=1 SIGN=$(SIGN)