diff --git a/Directory.Build.props b/Directory.Build.props
index dd98607..3de8d80 100644
--- a/Directory.Build.props
+++ b/Directory.Build.props
@@ -4,7 +4,11 @@
     <Company>begeistert</Company>
     <RepositoryUrl>https://github.com/PyMCU/RP2040Sharp</RepositoryUrl>
     <RepositoryType>git</RepositoryType>
-    <PackageLicenseExpression>MIT</PackageLicenseExpression>
+    <!-- The whole project is BUSL-1.1 (converts to MIT on the Change Date). nuget.org
+         rejects BUSL-1.1 as an SPDX expression, so we ship it as a packaged file. Each
+         packable project includes LICENSE-BUSL.txt via a <None Pack="true"> item. -->
+    <PackageLicenseExpression></PackageLicenseExpression>
+    <PackageLicenseFile>LICENSE-BUSL.txt</PackageLicenseFile>
     <PackageReadmeFile>README.md</PackageReadmeFile>
     <PackageProjectUrl>https://github.com/PyMCU/RP2040Sharp</PackageProjectUrl>
     <PackageTags>rp2040;raspberry-pi;emulator;cortex-m0plus;microcontroller;simulation</PackageTags>
diff --git a/LICENSE b/LICENSE
index dea9ca0..5ebab8b 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,4 +1,18 @@
-MIT License
+RP2040Sharp is licensed under the Business Source License 1.1 (BUSL-1.1).
+
+The full license text and parameters are in LICENSE-BUSL.txt. In summary: the
+entire project is initially BUSL-1.1 and automatically converts to the MIT
+License (the Change License) on the Change Date. Non-commercial, personal,
+hobby, educational, academic, evaluation and open-source use is free of charge;
+Commercial Use requires a separate commercial license (see LICENSE-BUSL.txt).
+
+Portions of the emulator core are derived from rp2040js
+(https://github.com/wokwi/rp2040js) by Uri Shaked, originally distributed under
+the MIT License. That original MIT copyright and permission notice is retained
+below and continues to apply to those portions.
+
+===============================================================================
+MIT License (applies to the rp2040js-derived portions of the emulator core)
 
 Copyright (c) 2026 Iván Montiel Cardona
 Copyright (c) 2026 Sergio Domínguez Rojas
diff --git a/LICENSE-BUSL.txt b/LICENSE-BUSL.txt
index d7964bc..869f1df 100644
--- a/LICENSE-BUSL.txt
+++ b/LICENSE-BUSL.txt
@@ -3,10 +3,15 @@ Business Source License 1.1
 Parameters
 
 Licensor:             Iván Montiel Cardona
-Licensed Work:        RP2040Sharp BUSL-1.1 components — RP2040Sharp.TestKit,
-                      RP2040Sharp.Wireless, and RP2040Sharp.TestKit.NanoFramework.
-                      (The RP2040Sharp emulator core is licensed separately under MIT.)
+Licensed Work:        RP2040Sharp — the complete RP2040 emulator: the emulator core
+                      (RP2040Sharp) and every package (RP2040Sharp.TestKit,
+                      RP2040Sharp.Wireless, RP2040Sharp.NanoFramework.TestKit).
                       The Licensed Work is © 2024-2026 Iván Montiel Cardona.
+
+                      Portions of the emulator core are derived from rp2040js
+                      (© Uri Shaked), originally under the MIT License; that MIT
+                      copyright and permission notice is retained in the LICENSE file
+                      and continues to apply to those portions.
 Additional Use Grant: You may copy, modify, create derivative works of, redistribute,
                       and make production use of the Licensed Work free of charge for
                       any use that is not a Commercial Use, as defined below.
diff --git a/src/RP2040Sharp/RP2040Sharp.csproj b/src/RP2040Sharp/RP2040Sharp.csproj
index a9453cf..5e741f8 100644
--- a/src/RP2040Sharp/RP2040Sharp.csproj
+++ b/src/RP2040Sharp/RP2040Sharp.csproj
@@ -11,6 +11,10 @@
     <DebugType>embedded</DebugType>
   </PropertyGroup>
 
+  <ItemGroup>
+    <None Include="..\..\LICENSE-BUSL.txt" Pack="true" PackagePath="" Visible="false" />
+  </ItemGroup>
+
   <ItemGroup>
     <EmbeddedResource Include="bootrom_b1.bin" />
     <EmbeddedResource Include="bootrom_b2.bin" />