aq1018 · Mar 29, 2026 · Mar 29, 2026 · Mar 29, 2026 · Apr 1, 2026 · Apr 2, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -13,7 +13,7 @@ jobs:
     name: Libraries
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - run: rustup toolchain install stable --profile minimal --component rustfmt,clippy
       - run: cargo fmt --all -- --check
       - run: cargo clippy -p tinyboot -p tinyboot-protocol --all-targets -- -D warnings
@@ -29,7 +29,7 @@ jobs:
       run:
         working-directory: tinyboot-cli
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - run: sudo apt-get update && sudo apt-get install -y libudev-dev
       - run: rustup toolchain install stable --profile minimal --component rustfmt,clippy
       - run: cargo fmt --all -- --check
@@ -43,34 +43,110 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        chip: [ch32v003f4p6, ch32v003a4m6, ch32v003f4u6, ch32v003j4m6]
+        include:
+          - chip: ch32v003f4p6
+            target: examples/ch32/boot/riscv32ec-unknown-none-elf.json
+            target-flags: -Zbuild-std=core -Zjson-target-spec
+          - chip: ch32v003a4m6
+            target: examples/ch32/boot/riscv32ec-unknown-none-elf.json
+            target-flags: -Zbuild-std=core -Zjson-target-spec
+          - chip: ch32v003f4u6
+            target: examples/ch32/boot/riscv32ec-unknown-none-elf.json
+            target-flags: -Zbuild-std=core -Zjson-target-spec
+          - chip: ch32v003j4m6
+            target: examples/ch32/boot/riscv32ec-unknown-none-elf.json
+            target-flags: -Zbuild-std=core -Zjson-target-spec
+          - chip: ch32v103c6t6
+            target: riscv32imc-unknown-none-elf
+            target-flags: ""
+          - chip: ch32v103c8t6
+            target: riscv32imc-unknown-none-elf
+            target-flags: ""
+          - chip: ch32v103c8u6
+            target: riscv32imc-unknown-none-elf
+            target-flags: ""
+          - chip: ch32v103r8t6
+            target: riscv32imc-unknown-none-elf
+            target-flags: ""
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@v6
       - name: Install toolchain
-        run: rustup toolchain install nightly --profile minimal --component rust-src,rustfmt,clippy
+        run: |
+          rustup toolchain install nightly --profile minimal --component rust-src,rustfmt,clippy,llvm-tools
+          rustup +nightly target add ${{ matrix.target }} 2>/dev/null || true
+          cargo install cargo-binutils
+          mkdir -p /tmp/sizes
       - name: Clippy libraries
-        run: cargo +nightly clippy -p tinyboot-ch32-hal -p tinyboot-ch32-boot -p tinyboot-ch32-app --features ${{ matrix.chip }} --target examples/ch32/boot/riscv32ec-unknown-none-elf.json -Zbuild-std=core -Zjson-target-spec -- -D warnings
+        run: cargo +nightly clippy -p tinyboot-ch32-hal -p tinyboot-ch32-boot -p tinyboot-ch32-app --features ${{ matrix.chip }} --target ${{ matrix.target }} ${{ matrix.target-flags }} -- -D warnings
       - name: Build libraries
-        run: cargo +nightly build -p tinyboot-ch32-hal -p tinyboot-ch32-boot -p tinyboot-ch32-app --features ${{ matrix.chip }} --target examples/ch32/boot/riscv32ec-unknown-none-elf.json -Zbuild-std=core -Zjson-target-spec --release
+        run: cargo +nightly build -p tinyboot-ch32-hal -p tinyboot-ch32-boot -p tinyboot-ch32-app --features ${{ matrix.chip }} --target ${{ matrix.target }} ${{ matrix.target-flags }} --release
       - name: Doc libraries
-        run: cargo +nightly doc -p tinyboot-ch32-hal -p tinyboot-ch32-boot -p tinyboot-ch32-app --features ${{ matrix.chip }} --target examples/ch32/boot/riscv32ec-unknown-none-elf.json -Zbuild-std=core -Zjson-target-spec --no-deps
+        run: cargo +nightly doc -p tinyboot-ch32-hal -p tinyboot-ch32-boot -p tinyboot-ch32-app --features ${{ matrix.chip }} --target ${{ matrix.target }} ${{ matrix.target-flags }} --no-deps
       - name: Fmt boot
         run: cd examples/ch32/boot && cargo +nightly fmt --all -- --check
       - name: Clippy boot (system-flash)
-        run: cd examples/ch32/boot && cargo +nightly clippy --features "${{ matrix.chip }},system-flash" -- -D warnings
+        run: cd examples/ch32/boot && cargo +nightly clippy --features "${{ matrix.chip }},system-flash" --target $(basename "${{ matrix.target }}") ${{ matrix.target-flags }} -- -D warnings
       - name: Build boot (system-flash)
-        run: cd examples/ch32/boot && cargo +nightly build --features "${{ matrix.chip }},system-flash" --release
+        run: |
+          cd examples/ch32/boot && cargo +nightly build --features "${{ matrix.chip }},system-flash" --target $(basename "${{ matrix.target }}") ${{ matrix.target-flags }} --release
+          TARGET_DIR=$(basename "${{ matrix.target }}" .json)
+          rust-size "target/$TARGET_DIR/release/boot" | tail -1 | awk '{print "${{ matrix.chip }},boot,system-flash," $4}' >> /tmp/sizes/sizes.csv
       - name: Clippy boot (user-flash)
-        run: cd examples/ch32/boot && cargo +nightly clippy --features "${{ matrix.chip }},user-flash" -- -D warnings
+        run: cd examples/ch32/boot && cargo +nightly clippy --features "${{ matrix.chip }},user-flash" --target $(basename "${{ matrix.target }}") ${{ matrix.target-flags }} -- -D warnings
       - name: Build boot (user-flash)
-        run: cd examples/ch32/boot && cargo +nightly build --features "${{ matrix.chip }},user-flash" --release
+        run: |
+          cd examples/ch32/boot && cargo +nightly build --features "${{ matrix.chip }},user-flash" --target $(basename "${{ matrix.target }}") ${{ matrix.target-flags }} --release
+          TARGET_DIR=$(basename "${{ matrix.target }}" .json)
+          rust-size "target/$TARGET_DIR/release/boot" | tail -1 | awk '{print "${{ matrix.chip }},boot,user-flash," $4}' >> /tmp/sizes/sizes.csv
       - name: Fmt app
         run: cd examples/ch32/app && cargo +nightly fmt --all -- --check
       - name: Clippy app (system-flash)
-        run: cd examples/ch32/app && cargo +nightly clippy --features "${{ matrix.chip }},system-flash" -- -D warnings
+        run: cd examples/ch32/app && cargo +nightly clippy --features "${{ matrix.chip }},system-flash" --target $(basename "${{ matrix.target }}") ${{ matrix.target-flags }} -- -D warnings
       - name: Build app (system-flash)
-        run: cd examples/ch32/app && cargo +nightly build --features "${{ matrix.chip }},system-flash" --release
+        run: |
+          cd examples/ch32/app && cargo +nightly build --features "${{ matrix.chip }},system-flash" --target $(basename "${{ matrix.target }}") ${{ matrix.target-flags }} --release
+          TARGET_DIR=$(basename "${{ matrix.target }}" .json)
+          rust-size "target/$TARGET_DIR/release/app" | tail -1 | awk '{print "${{ matrix.chip }},app,system-flash," $4}' >> /tmp/sizes/sizes.csv
       - name: Clippy app (user-flash)
-        run: cd examples/ch32/app && cargo +nightly clippy --features "${{ matrix.chip }},user-flash" -- -D warnings
+        run: cd examples/ch32/app && cargo +nightly clippy --features "${{ matrix.chip }},user-flash" --target $(basename "${{ matrix.target }}") ${{ matrix.target-flags }} -- -D warnings
       - name: Build app (user-flash)
-        run: cd examples/ch32/app && cargo +nightly build --features "${{ matrix.chip }},user-flash" --release
+        run: |
+          cd examples/ch32/app && cargo +nightly build --features "${{ matrix.chip }},user-flash" --target $(basename "${{ matrix.target }}") ${{ matrix.target-flags }} --release
+          TARGET_DIR=$(basename "${{ matrix.target }}" .json)
+          rust-size "target/$TARGET_DIR/release/app" | tail -1 | awk '{print "${{ matrix.chip }},app,user-flash," $4}' >> /tmp/sizes/sizes.csv
+      - name: Upload sizes
+        uses: actions/upload-artifact@v6
+        with:
+          name: sizes-${{ matrix.chip }}
+          path: /tmp/sizes/sizes.csv
+
+  size-report:
+    name: Size Report
+    if: github.event_name == 'pull_request'
+    needs: ch32
+    runs-on: ubuntu-latest
+    permissions:
+      pull-requests: write
+    steps:
+      - name: Download all size artifacts
+        uses: actions/download-artifact@v8
+        with:
+          pattern: sizes-*
+          path: /tmp/sizes
+      - name: Generate size table
+        run: |
+          cat /tmp/sizes/*/sizes.csv | sort -t, -k3,3 -k2,2r -k1,1 > /tmp/all-sizes.csv
+          CSV=/tmp/all-sizes.csv
+          {
+            echo "## Binary Sizes"
+            echo ""
+            echo "| Chip | Example | Mode | Size |"
+            echo "|------|---------|------|-----:|"
+            while IFS=, read -r chip crate flash size; do
+              echo "| \`$chip\` | $crate | $flash | $size |"
+            done < "$CSV"
+          } > /tmp/sizes/comment.md
+      - name: Post PR comment
+        uses: marocchino/sticky-pull-request-comment@v3
+        with:
+          path: /tmp/sizes/comment.md
diff --git a/.zed/settings.json b/.zed/settings.json
@@ -1,21 +1,32 @@
 {
   "languages": {
     "Rust": {
-      "format_on_save": "on"
-    }
+      "format_on_save": "on",
+    },
   },
   "lsp": {
     "rust-analyzer": {
       "initialization_options": {
         "cargo": {
-          "target": "riscv32imac-unknown-none-elf",
-          "features": ["ch32v003f4p6", "system-flash"]
+          "target": "riscv32imc-unknown-none-elf",
+          "features": [
+            // "ch32v003f4u6"
+            "ch32v103c8u6",
+            // "user-flash",
+            "system-flash",
+          ],
         },
         "check": {
           "command": "clippy",
-          "allTargets": false
-        }
-      }
-    }
-  }
+          "allTargets": false,
+        },
+        "linkedProjects": [
+          "Cargo.toml",
+          // "tinyboot-cli/Cargo.toml",
+          "examples/ch32/boot/Cargo.toml",
+          "examples/ch32/app/Cargo.toml",
+        ],
+      },
+    },
+  },
 }
diff --git a/README.md b/README.md
@@ -6,7 +6,7 @@ Rust bootloader for resource-constrained microcontrollers. Fits in the CH32V003'
 
 ## Chip Compatibility
 
-tinyboot currently supports **UART / RS-485** transport. The table below tracks chip support status.
+tinyboot currently supports **UART / RS-485** transport. The table below tracks chip support status. Chips with hardware boot pins (e.g. BOOT0/BOOT1) require a small external circuit to allow firmware-controlled boot mode switching. Please see [GPIO-Controlled Boot Mode Selection](docs/boot-ctl.md) document for more information.
 
 ✅ Verified | ❓ Untested (same die, likely works — volunteer needed) | 📋 Planned
 

diff --git a/docs/boot-ctl-flip-flop.png b/docs/boot-ctl-flip-flop.png
diff --git a/docs/boot-ctl-rc.png b/docs/boot-ctl-rc.png
diff --git a/docs/boot-ctl.md b/docs/boot-ctl.md
@@ -0,0 +1,73 @@
+# GPIO-Controlled Boot Mode Selection
+
+Some MCUs (e.g. CH32V103) use hardware boot pins (BOOT0/BOOT1) to select the boot
+source at reset. If you choose to run tinyboot from system flash, you need BOOT0
+to default HIGH on power-on (system flash), and provide a way for firmware to
+switch to user flash (BOOT0 LOW) across a reset.
+
+This document describes two circuits for controlling BOOT0 from a single GPIO pin
+(BOOT_CTL). Both share the same firmware interface.
+
+Note: BOOT1 is tied to GND in both circuits.
+
+## BOOT_CTL GPIO Truth Table
+
+| BOOT_CTL           | Effect                        |
+| ------------------ | ----------------------------- |
+| HIGH               | Boots system flash (tinyboot) |
+| LOW                | Boots user flash (app)        |
+
+## Circuit Option 1: RC (Recommended)
+
+![RC Circuit](boot-ctl-rc.png)
+
+**How it works:**
+
+- R1 (10K) pulls BOOT0 HIGH by default (system flash).
+- When BOOT_CTL drives LOW, it overpowers the pull-up through R2 (1K), pulling
+  BOOT0 LOW and discharging C1.
+- On reset, the GPIO goes Hi-Z. The discharged capacitor holds BOOT0 LOW long
+  enough for the chip to sample it (RC time constant = 10K x 100nF = 1ms).
+- The capacitor then recharges through R1, returning BOOT0 to HIGH. On any
+  subsequent reset, the chip boots back into system flash automatically.
+
+**Tested:** Yes, verified on CH32V103C8T6. The RC time constant of 1ms provides
+sufficient hold time across a software-triggered system reset. The capacitor
+charges fast enough during power-on reset (POR) that BOOT0 reads HIGH on first
+boot.
+
+## Circuit Option 2: Flip-Flop
+
+![Flip-Flop Circuit](boot-ctl-flip-flop.png)
+
+**How it works:**
+
+- The NPN transistor inverts BOOT_CTL to drive /PRE (active-low preset).
+- BOOT_CTL drives /CLR (active-low clear) directly through a 1K series resistor.
+- When BOOT_CTL = HIGH: transistor ON, /PRE = LOW (active), Q = HIGH (system flash).
+- When BOOT_CTL = LOW: transistor OFF, /CLR = LOW (active), Q = LOW (user flash).
+- When BOOT_CTL = Hi-Z (during reset): transistor OFF (/PRE inactive via pull-up),
+  /CLR inactive (via pull-up). The flip-flop holds its previous state.
+- The two 1K series resistors isolate the transistor base from /CLR, preventing
+  the /CLR pull-up from turning on the transistor during Hi-Z.
+
+**Power-on state:** The 74AUC1G74 does not have a guaranteed power-on state. An
+optional 100nF capacitor from /PRE to GND can be added to force Q HIGH on first
+power-up.
+
+**Tested:** Not yet verified on hardware. The design is sound in theory but has not
+been tested. Let me know if you can confirm that it works.
+
+## Which to Choose
+
+The RC circuit is simpler (3 passive components, no IC) and has been validated on
+hardware. It relies on the capacitor holding BOOT0 LOW for ~1ms across a reset,
+which is well within the margin for software-triggered resets.
+
+The flip-flop circuit is deterministic (no timing dependency) and holds state
+indefinitely, but requires more components and has not been tested. It may be
+preferable in designs if you need reliable state retention, e.g. a real product
+that requires high reliability.
+
+For most use cases though, my personal opinion is the RC circuit is probably reliable
+enough and simpler / lower cost.
diff --git a/examples/ch32/app/.cargo/config.toml b/examples/ch32/app/.cargo/config.toml
@@ -12,6 +12,13 @@ rustflags = [
 ]
 runner = "probe-rs run --chip CH32V003"
 
+[target.riscv32imc-unknown-none-elf]
+rustflags = [
+  "-C", "link-arg=-Tlink.x",
+  "-C", "link-arg=--nmagic",
+]
+runner = "probe-rs run --chip CH32V103"
+
 [env]
 DEFMT_LOG = "trace"
 DEFMT_RTT_BUFFER_SIZE = "128"
diff --git a/examples/ch32/app/Cargo.toml b/examples/ch32/app/Cargo.toml
@@ -8,17 +8,21 @@ tinyboot-ch32-app = { path = "../../../tinyboot-ch32-app", default-features = fa
 embedded-io = "0.7"
 critical-section = "1"
 ch32-hal = { git = "https://github.com/ch32-rs/ch32-hal", default-features = false }
-qingke-rt = { version = "0.6", features = ["v2"] }
+qingke-rt = { version = "0.6", default-features = false }
 defmt = { version = "1.0", optional = true }
 defmt-rtt = { version = "1.1", optional = true }
 
 [features]
 system-flash = ["tinyboot-ch32-app/system-flash"]
 user-flash = ["dep:defmt", "dep:defmt-rtt", "tinyboot-ch32-app/defmt"]
-ch32v003f4p6 = ["tinyboot-ch32-app/ch32v003f4p6", "ch32-hal/ch32v003f4p6", "ch32-hal/rt"]
-ch32v003a4m6 = ["tinyboot-ch32-app/ch32v003a4m6", "ch32-hal/ch32v003a4m6", "ch32-hal/rt"]
-ch32v003f4u6 = ["tinyboot-ch32-app/ch32v003f4u6", "ch32-hal/ch32v003f4u6", "ch32-hal/rt"]
-ch32v003j4m6 = ["tinyboot-ch32-app/ch32v003j4m6", "ch32-hal/ch32v003j4m6", "ch32-hal/rt"]
+ch32v003f4p6 = ["tinyboot-ch32-app/ch32v003f4p6", "ch32-hal/ch32v003f4p6", "ch32-hal/rt", "qingke-rt/v2"]
+ch32v003a4m6 = ["tinyboot-ch32-app/ch32v003a4m6", "ch32-hal/ch32v003a4m6", "ch32-hal/rt", "qingke-rt/v2"]
+ch32v003f4u6 = ["tinyboot-ch32-app/ch32v003f4u6", "ch32-hal/ch32v003f4u6", "ch32-hal/rt", "qingke-rt/v2"]
+ch32v003j4m6 = ["tinyboot-ch32-app/ch32v003j4m6", "ch32-hal/ch32v003j4m6", "ch32-hal/rt", "qingke-rt/v2"]
+ch32v103c6t6 = ["tinyboot-ch32-app/ch32v103c6t6", "ch32-hal/ch32v103c6t6", "ch32-hal/rt", "qingke-rt/v3"]
+ch32v103c8t6 = ["tinyboot-ch32-app/ch32v103c8t6", "ch32-hal/ch32v103c8t6", "ch32-hal/rt", "qingke-rt/v3"]
+ch32v103c8u6 = ["tinyboot-ch32-app/ch32v103c8u6", "ch32-hal/ch32v103c8u6", "ch32-hal/rt", "qingke-rt/v3"]
+ch32v103r8t6 = ["tinyboot-ch32-app/ch32v103r8t6", "ch32-hal/ch32v103r8t6", "ch32-hal/rt", "qingke-rt/v3"]
 
 [profile.dev]
 opt-level = "z"

diff --git a/examples/ch32/app/build.rs b/examples/ch32/app/build.rs
@@ -12,6 +12,10 @@ fn main() {
         "CARGO_FEATURE_CH32V003A4M6",
         "CARGO_FEATURE_CH32V003F4U6",
         "CARGO_FEATURE_CH32V003J4M6",
+        "CARGO_FEATURE_CH32V103C6T6",
+        "CARGO_FEATURE_CH32V103C8T6",
+        "CARGO_FEATURE_CH32V103C8U6",
+        "CARGO_FEATURE_CH32V103R8T6",
     ];
     let selected: Vec<&str> = chips.iter().filter(|c| cfg_has(c)).copied().collect();
     if selected.len() != 1 {
@@ -37,9 +41,9 @@ fn main() {
     println!("cargo:rustc-link-search={out_dir}");
     println!("cargo:rerun-if-changed=memory_x");
     println!("cargo:rustc-link-arg=-Ttb-app.x");
+    println!("cargo:rustc-link-arg=-Ttb-boot-req.x");
 
     if user_flash {
-        println!("cargo:rustc-link-arg=-Ttb-user-flash.x");
         println!("cargo:rustc-link-arg=--wrap=_setup_interrupts");
         println!("cargo:rustc-link-arg=-Tdefmt.x");
     }

diff --git a/examples/ch32/app/memory_x/system-flash/ch32v103c6t6.x b/examples/ch32/app/memory_x/system-flash/ch32v103c6t6.x
@@ -0,0 +1,21 @@
+/* CH32V103 application memory layout for system-flash bootloader.
+ *
+ * The application occupies the full 32KB user flash. The bootloader lives
+ * in the separate system flash region, so no space is reserved here.
+ *
+ * Addresses use the code-execution alias (0x0000_0000 base).
+ * The FPEC programming offset (0x0800_0000) is handled by the HAL.
+ */
+MEMORY
+{
+    FLASH : ORIGIN = 0x00000000, LENGTH = 32K
+    RAM   : ORIGIN = 0x20000000, LENGTH = 10K
+}
+
+/* Region aliases required by qingke-rt's linker script. */
+REGION_ALIAS("REGION_TEXT", FLASH);
+REGION_ALIAS("REGION_RODATA", FLASH);
+REGION_ALIAS("REGION_DATA", RAM);
+REGION_ALIAS("REGION_BSS", RAM);
+REGION_ALIAS("REGION_HEAP", RAM);
+REGION_ALIAS("REGION_STACK", RAM);
diff --git a/examples/ch32/app/memory_x/system-flash/ch32v103c8t6.x b/examples/ch32/app/memory_x/system-flash/ch32v103c8t6.x
@@ -0,0 +1,21 @@
+/* CH32V103 application memory layout for system-flash bootloader.
+ *
+ * The application occupies the full 64KB user flash. The bootloader lives
+ * in the separate system flash region, so no space is reserved here.
+ *
+ * Addresses use the code-execution alias (0x0000_0000 base).
+ * The FPEC programming offset (0x0800_0000) is handled by the HAL.
+ */
+MEMORY
+{
+    FLASH : ORIGIN = 0x00000000, LENGTH = 64K
+    RAM   : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+/* Region aliases required by qingke-rt's linker script. */
+REGION_ALIAS("REGION_TEXT", FLASH);
+REGION_ALIAS("REGION_RODATA", FLASH);
+REGION_ALIAS("REGION_DATA", RAM);
+REGION_ALIAS("REGION_BSS", RAM);
+REGION_ALIAS("REGION_HEAP", RAM);
+REGION_ALIAS("REGION_STACK", RAM);
diff --git a/examples/ch32/app/memory_x/system-flash/ch32v103c8u6.x b/examples/ch32/app/memory_x/system-flash/ch32v103c8u6.x
@@ -0,0 +1,21 @@
+/* CH32V103 application memory layout for system-flash bootloader.
+ *
+ * The application occupies the full 64KB user flash. The bootloader lives
+ * in the separate system flash region, so no space is reserved here.
+ *
+ * Addresses use the code-execution alias (0x0000_0000 base).
+ * The FPEC programming offset (0x0800_0000) is handled by the HAL.
+ */
+MEMORY
+{
+    FLASH : ORIGIN = 0x00000000, LENGTH = 64K
+    RAM   : ORIGIN = 0x20000000, LENGTH = 20K
+}
+
+/* Region aliases required by qingke-rt's linker script. */
+REGION_ALIAS("REGION_TEXT", FLASH);
+REGION_ALIAS("REGION_RODATA", FLASH);
+REGION_ALIAS("REGION_DATA", RAM);
+REGION_ALIAS("REGION_BSS", RAM);
+REGION_ALIAS("REGION_HEAP", RAM);
+REGION_ALIAS("REGION_STACK", RAM);