diff --git a/build.gradle.kts b/build.gradle.kts
index 30114a0..7bbd7fc 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -115,7 +115,23 @@ android {
 }
 
 val buildSecp256k1 by tasks.creating { group = "build" }
-fun creatingBuildSecp256k1(target: String, cross: String? = null, env: String = "", configuration: Task.() -> Unit = {}) = tasks.creating(Exec::class) {
+sealed class Cross {
+    abstract fun cmd(target: String, nativeDir: File): List<String>
+    class DockCross(val cross: String) : Cross() {
+        override fun cmd(target: String, nativeDir: File): List<String> = listOf("./dockcross-$cross", "bash", "-c", "TARGET=$target ./build.sh")
+    }
+    class MultiArch(val crossTriple: String) : Cross() {
+        override fun cmd(target: String, nativeDir: File): List<String> {
+            val uid = Runtime.getRuntime().exec("id -u").inputStream.use { it.reader().readText() }.trim().toInt()
+            return listOf(
+                "docker", "run", "--rm", "-v", "${nativeDir.absolutePath}:/workdir",
+                "-e", "CROSS_TRIPLE=$crossTriple", "-e", "TARGET=$target", "-e", "TO_UID=$uid",
+                "multiarch/crossbuild", "./build.sh"
+            )
+        }
+    }
+}
+fun creatingBuildSecp256k1(target: String, cross: Cross?) = tasks.creating(Exec::class) {
     group = "build"
     buildSecp256k1.dependsOn(this)
 
@@ -124,15 +140,11 @@ fun creatingBuildSecp256k1(target: String, cross: String? = null, env: String =
 
     workingDir = projectDir.resolve("native")
     environment("TARGET", target)
-    if (cross == null) commandLine("./build.sh")
-    else commandLine("./dockcross-$cross", "bash", "-c", "TARGET=$target ./build.sh")
-
-    configuration()
+    commandLine((cross?.cmd(target, workingDir) ?: emptyList()) + "./build.sh")
 }
-
-val buildSecp256k1Darwin by creatingBuildSecp256k1("darwin")
-val buildSecp256k1Linux by creatingBuildSecp256k1("linux", cross = if (currentOs.isMacOsX) "linux-x64" else null)
-val buildSecp256k1Mingw by creatingBuildSecp256k1("mingw", cross = "windows-x64", env = "CONF_OPTS=--host=x86_64-w64-mingw32")
+val buildSecp256k1Darwin by creatingBuildSecp256k1("darwin", if (currentOs.isMacOsX) null else Cross.MultiArch("x86_64-apple-darwin"))
+val buildSecp256k1Linux by creatingBuildSecp256k1("linux", if (currentOs.isLinux) null else Cross.DockCross("linux-x64"))
+val buildSecp256k1Mingw by creatingBuildSecp256k1("mingw", if (currentOs.isWindows) null else Cross.DockCross("windows-x64"))
 
 val copyJni by tasks.creating(Sync::class) {
     dependsOn(buildSecp256k1)
@@ -146,6 +158,8 @@ val buildSecp256k1Ios by tasks.creating(Exec::class) {
     group = "build"
     buildSecp256k1.dependsOn(this)
 
+    onlyIf { currentOs.isMacOsX }
+
     inputs.files(projectDir.resolve("native/build-ios.sh"))
     outputs.dir(projectDir.resolve("native/build/ios"))
 
@@ -153,7 +167,10 @@ val buildSecp256k1Ios by tasks.creating(Exec::class) {
     commandLine("./build-ios.sh")
 }
 
-val buildSecp256k1Android by tasks.creating { group = "build" }
+val buildSecp256k1Android by tasks.creating {
+    group = "build"
+    buildSecp256k1.dependsOn(this)
+}
 fun creatingBuildSecp256k1Android(arch: String) = tasks.creating(Exec::class) {
     group = "build"
     buildSecp256k1Android.dependsOn(this)
@@ -164,8 +181,10 @@ fun creatingBuildSecp256k1Android(arch: String) = tasks.creating(Exec::class) {
     workingDir = projectDir.resolve("native")
 
     val toolchain = when {
+        currentOs.isLinux -> "linux-x86_64"
         currentOs.isMacOsX -> "darwin-x86_64"
-        else -> error("Cannot build for Android on this OS")
+        currentOs.isWindows -> "windows-x86_64"
+        else -> error("No Android toolchain defined for this OS: $currentOs")
     }
     environment("TOOLCHAIN", toolchain)
     environment("ARCH", arch)
diff --git a/native/build-android.sh b/native/build-android.sh
index d57acdc..d36522f 100755
--- a/native/build-android.sh
+++ b/native/build-android.sh
@@ -1,9 +1,6 @@
 #!/usr/bin/env bash
 set -e
 
-ANDROID_NDK=/Users/salomonbrys/Library/Android/sdk/ndk/21.3.6528147
-TOOLCHAIN=darwin-x86_64
-
 [[ -z "$ANDROID_NDK" ]] && echo "Please set the ANDROID_NDK variable" && exit 1
 [[ -z "$ARCH" ]] && echo "Please set the ARCH variable" && exit 1
 [[ -z "$TOOLCHAIN" ]] && echo "Please set the TOOLCHAIN variable" && exit 1
diff --git a/native/build.sh b/native/build.sh
index 3f891c8..94fb98c 100755
--- a/native/build.sh
+++ b/native/build.sh
@@ -1,7 +1,11 @@
 #!/usr/bin/env bash
 set -e
 
-[[ -z "$TARGET" ]] && echo "Please set the PLATFORM variable" && exit 1
+[[ -z "$TARGET" ]] && echo "Please set the TARGET variable" && exit 1
+
+if [ "$(id -u)" == "0" ]; then
+  [[ -z "$TO_UID" ]] && echo "Please set the TO_UID variable" && exit 1
+fi
 
 cd secp256k1
 
@@ -9,6 +13,8 @@ if [ "$TARGET" == "mingw" ]; then
   CONF_OPTS="CFLAGS=-fpic --host=x86_64-w64-mingw32"
 elif [ "$TARGET" == "linux" ]; then
   CONF_OPTS="CFLAGS=-fpic"
+elif [ "$TARGET" == "darwin" ]; then
+  CONF_OPTS="--host=x86_64-w64-darwin"
 fi
 
 ./autogen.sh
@@ -16,19 +22,26 @@ fi
 make clean
 make
 
+[[ ! -z "$TO_UID" ]] && chown -R $TO_UID:$TO_UID .
+
 cd ..
 
 mkdir -p build/$TARGET
 cp -v secp256k1/.libs/libsecp256k1.a build/$TARGET/
 
+[[ ! -z "$TO_UID" ]] && chown -R $TO_UID:$TO_UID build
+
 CC=gcc
 JNI_HEADERS=$TARGET
 
 if [ "$TARGET" == "linux" ]; then
   OUTFILE=libsecp256k1-jni.so
+    ADD_LIB=-lgmp
 elif [ "$TARGET" == "darwin" ]; then
   OUTFILE=libsecp256k1-jni.dylib
-  ADD_LIB=-lgmp
+  if [ -z "$CROSS_TRIPLE" ]; then
+    ADD_LIB=-lgmp
+  fi
 elif [ "$TARGET" == "mingw" ]; then
   OUTFILE=secp256k1-jni.dll
   CC=/usr/src/mxe/usr/bin/x86_64-w64-mingw32.static-gcc
@@ -37,3 +50,7 @@ elif [ "$TARGET" == "mingw" ]; then
 fi
 
 $CC -shared $CC_OPTS -o build/$TARGET/$OUTFILE jni/src/org_bitcoin_NativeSecp256k1.c jni/src/org_bitcoin_Secp256k1Context.c -Ijni/headers/ -Ijni/headers/$JNI_HEADERS/ -Isecp256k1/ -lsecp256k1 -Lbuild/$TARGET/ $ADD_LIB
+
+[[ ! -z "$TO_UID" ]] && chown -R $TO_UID:$TO_UID build
+
+echo "Build done for $TARGET"
diff --git a/src/nativeInterop/cinterop/libsecp256k1.def b/src/nativeInterop/cinterop/libsecp256k1.def
index 849e578..eec43c9 100644
--- a/src/nativeInterop/cinterop/libsecp256k1.def
+++ b/src/nativeInterop/cinterop/libsecp256k1.def
@@ -5,7 +5,7 @@ headerFilter = secp256k1/** secp256k1_ecdh.h secp256k1_recovery.h secp256k1.h
 
 staticLibraries.linux = libsecp256k1.a
 libraryPaths.linux = c/secp256k1/build/linux/
-linkerOpts.linux = -L/usr/lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/local/lib
+linkerOpts.linux = -L/usr/lib64 -L/usr/lib/x86_64-linux-gnu -L/usr/local/lib -lgmp
 
 staticLibraries.ios = libsecp256k1.a
 libraryPaths.ios = c/secp256k1/build/ios/ /usr/local/lib