diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 44ec6cb..def5259 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -20,6 +20,7 @@ jobs:
       - uses: actions/checkout@v4
         with:
           persist-credentials: false
+          submodules: true
       - name: Set up Ruby
         uses: ruby/setup-ruby@v1
         with:
diff --git a/.gitmodules b/.gitmodules
index 4e3fc4e..7702456 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,4 @@
 [submodule "vendor/spinel"]
 	path = vendor/spinel
 	url = https://github.com/matz/spinel
+	branch = self-host
diff --git a/.rubocop.yml b/.rubocop.yml
index ae378d0..a29cd67 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,5 +1,19 @@
 AllCops:
   TargetRubyVersion: 3.2
+  NewCops: disable
+  Exclude:
+    - "vendor/**/*"
+    - "examples/**/*.rb"
+    - "lib/rubyduino/arduino_uno.rb"
+    - "lib/rubyduino/spinel_arduino_codegen.rb"
+
+Metrics/MethodLength:
+  Exclude:
+    - "bin/rubyduino"
+
+Style/SoleNestedConditional:
+  Exclude:
+    - "bin/rubyduino"
 
 Style/StringLiterals:
   EnforcedStyle: double_quotes
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6f246a3..46a6807 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 ## [Unreleased]
 
+## [0.2.1] - 2026-08-19
+
+- Update vendored Spinel to `b80ba94b` from the compatible `self-host` branch
+- Adapt Arduino code generation to Spinel's separate analysis and codegen pipeline
+- Add the `sp_Class` value type and integer arithmetic helpers required by the updated code generator to the AVR runtime
+
 ## [0.2.0] - 2026-05-08
 
 - Expand the ArduinoUNO API with PWM, microsecond delays, millis/micros timing, pulse measurement, serial I/O, shift helpers, and interrupt control
diff --git a/lib/rubyduino/sp_runtime.h b/lib/rubyduino/sp_runtime.h
index 2769cab..af50d7e 100644
--- a/lib/rubyduino/sp_runtime.h
+++ b/lib/rubyduino/sp_runtime.h
@@ -19,6 +19,15 @@ typedef struct {
   mrb_int last;
 } sp_Range;
 
+typedef struct {
+  mrb_int cls_id;
+} sp_Class;
+
+#define sp_int_add(a, b) ((mrb_int)((a) + (b)))
+#define sp_int_sub(a, b) ((mrb_int)((a) - (b)))
+#define sp_int_mul(a, b) ((mrb_int)((a) * (b)))
+#define sp_int_neg(a) ((mrb_int)(-(a)))
+
 #ifndef TRUE
 #define TRUE 1
 #endif
diff --git a/lib/rubyduino/spinel.rb b/lib/rubyduino/spinel.rb
index b187d01..c4dbd28 100644
--- a/lib/rubyduino/spinel.rb
+++ b/lib/rubyduino/spinel.rb
@@ -2,7 +2,7 @@
 
 module Rubyduino
   module Spinel
-    COMMIT = "e7f714f213ca572912f7214f358a927f8e2152e5"
+    COMMIT = "b80ba94b7163e822b34758b1de1555a3da32374b"
     ROOT = File.expand_path("../../vendor/spinel", __dir__)
   end
 end
diff --git a/lib/rubyduino/spinel_arduino_codegen.rb b/lib/rubyduino/spinel_arduino_codegen.rb
index 940cf04..1739e73 100644
--- a/lib/rubyduino/spinel_arduino_codegen.rb
+++ b/lib/rubyduino/spinel_arduino_codegen.rb
@@ -1,9 +1,12 @@
 #!/usr/bin/env ruby
 # Arduino UNO codegen layer for Spinel.
 #
-# This file intentionally leaves spinel_codegen.rb unchanged. Spinel's codegen
-# file is CLI-oriented, so we load only its Compiler definition and keep the
-# same AST-file input/output-file flow as the upstream footer.
+# This file intentionally leaves Spinel's analyzer and code generator unchanged.
+# It runs the upstream analysis phase, then loads only the Compiler definition
+# from the CLI-oriented code generator before applying the Arduino extensions.
+
+require "rbconfig"
+require "tempfile"
 
 ROOT = File.expand_path("../..", __dir__)
 SPINEL_ROOT = File.join(ROOT, "vendor/spinel")
@@ -11,7 +14,7 @@
 def load_spinel_compiler
   path = File.join(SPINEL_ROOT, "spinel_codegen.rb")
   source = File.read(path)
-  marker = "\n# ---- Main ----\n"
+  marker = "\n# ---- Main (codegen) ----\n"
   split_at = source.index(marker)
   unless split_at
     warn "spinel_arduino_codegen: cannot find codegen main marker"
@@ -106,13 +109,20 @@ def integer_literal_node?(nid)
   exit(1)
 end
 
-compiler = Compiler.new
-compiler.read_text_ast(File.read(ast_file))
-compiler.compile
-
-result = compiler.build_output
-if out_file
-  File.write(out_file, result)
-else
-  print result
+analyzer = File.join(SPINEL_ROOT, "spinel_analyze.rb")
+Tempfile.create(["spinel-analysis", ".ir"]) do |ir_file|
+  ir_file.close
+  abort "spinel_arduino_codegen: analysis failed" unless system(RbConfig.ruby, analyzer, ast_file, ir_file.path)
+
+  compiler = Compiler.new
+  compiler.read_text_ast(File.read(ast_file))
+  compiler.load_analysis_buf(File.read(ir_file.path))
+  compiler.generate_code
+
+  result = compiler.build_output
+  if out_file
+    File.write(out_file, result)
+  else
+    print result
+  end
 end
diff --git a/lib/rubyduino/version.rb b/lib/rubyduino/version.rb
index d512231..10fc7d4 100644
--- a/lib/rubyduino/version.rb
+++ b/lib/rubyduino/version.rb
@@ -1,5 +1,5 @@
 # frozen_string_literal: true
 
 module Rubyduino
-  VERSION = "0.2.0"
+  VERSION = "0.2.1"
 end
diff --git a/rubyduino.gemspec b/rubyduino.gemspec
index abb4afa..ae169c2 100644
--- a/rubyduino.gemspec
+++ b/rubyduino.gemspec
@@ -9,7 +9,8 @@ Gem::Specification.new do |spec|
   spec.email = ["joseph.schito@gmail.com"]
 
   spec.summary = "Compile Ruby sketches for Arduino boards."
-  spec.description = "Rubyduino compiles Ruby code for Arduino boards and uploads the generated firmware over a serial port."
+  spec.description = "Rubyduino compiles Ruby code for Arduino boards " \
+                     "and uploads the generated firmware over a serial port."
   spec.homepage = "https://github.com/josephschito/rubyduino"
   spec.license = "MIT"
   spec.required_ruby_version = ">= 3.2.0"
@@ -27,7 +28,7 @@ Gem::Specification.new do |spec|
       (f == gemspec) ||
         (f == "vendor/spinel") ||
         f.start_with?(*%w[Gemfile .gitignore test/ .github/ .rubocop.yml]) ||
-        (%w[bin/console bin/setup].include?(f))
+        %w[bin/console bin/setup].include?(f)
     end
   end
 
diff --git a/test/test_rubyduino.rb b/test/test_rubyduino.rb
index a1b9b06..5e3a0ac 100644
--- a/test/test_rubyduino.rb
+++ b/test/test_rubyduino.rb
@@ -8,7 +8,7 @@ def test_that_it_has_a_version_number
   end
 
   def test_spinel_snapshot_is_available
-    assert_equal "e7f714f213ca572912f7214f358a927f8e2152e5", Rubyduino::Spinel::COMMIT
+    assert_equal "b80ba94b7163e822b34758b1de1555a3da32374b", Rubyduino::Spinel::COMMIT
     assert_path_exists File.join(Rubyduino::Spinel::ROOT, "README.md")
   end
 
@@ -18,6 +18,7 @@ def test_gemspec_packages_spinel_files
     assert_includes spec.files, "bin/rubyduino"
     assert_includes spec.files, "lib/rubyduino/spinel_arduino_codegen.rb"
     assert_includes spec.files, "vendor/spinel/README.md"
+    assert_includes spec.files, "vendor/spinel/spinel_analyze.rb"
     assert_includes spec.files, "vendor/spinel/spinel_codegen.rb"
     refute_includes spec.files, "vendor/spinel/.git"
   end
diff --git a/vendor/spinel b/vendor/spinel
index e7f714f..b80ba94 160000
--- a/vendor/spinel
+++ b/vendor/spinel
@@ -1 +1 @@
-Subproject commit e7f714f213ca572912f7214f358a927f8e2152e5
+Subproject commit b80ba94b7163e822b34758b1de1555a3da32374b