diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 4ddce88..1026e82 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -29,4 +29,4 @@ jobs:
         version: master
 
     - name: Build tests
-      run: zig build -Drelease-small
+      run: zig build -Doptimize=ReleaseSmall
diff --git a/build.zig b/build.zig
index 86b4f48..304c3d7 100644
--- a/build.zig
+++ b/build.zig
@@ -10,7 +10,10 @@ const chips = microzig.chips;
 const Backing = microzig.Backing;
 
 pub fn build(b: *std.build.Builder) !void {
-    const mode = b.standardReleaseOptions();
+    // Standard optimization options allow the person running `zig build -Doptimize=...` to select
+    // between Debug, ReleaseSafe, ReleaseFast, and ReleaseSmall. Here we do not
+    // set a preferred release mode, allowing the user to decide how to optimize.
+    const optimize = b.standardOptimizeOption(.{});
 
     const test_step = b.step("test", "Builds and runs the library test suite");
 
@@ -52,11 +55,10 @@ pub fn build(b: *std.build.Builder) !void {
                 b.fmt("test-{s}-{s}.elf", .{ tst.name, cfg.name }),
                 tst.source,
                 cfg.backing,
-                .{},
+                .{.optimize = optimize },
             );
 
             if (filter == null or exe.inner.target.cpu_arch.? == filter.?) {
-                exe.inner.setBuildMode(mode);
                 exe.inner.install();
 
                 test_step.dependOn(&exe.inner.step);
diff --git a/src/main.zig b/src/main.zig
index 289502f..ff4c6f9 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -32,6 +32,7 @@ pub const BuildOptions = struct {
     // a hal package is a package with ergonomic wrappers for registers for a
     // given mcu, it's only dependency can be microzig
     hal_package_path: ?std.build.FileSource = null,
+    optimize: std.builtin.OptimizeMode = std.builtin.OptimizeMode.Debug,
 };
 
 pub const EmbeddedExecutable = struct {
@@ -56,10 +57,6 @@ pub const EmbeddedExecutable = struct {
         });
     }
 
-    pub fn setBuildMode(exe: *EmbeddedExecutable, mode: std.builtin.Mode) void {
-        exe.inner.setBuildMode(mode);
-    }
-
     pub fn install(exe: *EmbeddedExecutable) void {
         exe.inner.install();
     }
@@ -177,7 +174,7 @@ pub fn addEmbeddedExecutable(
     };
 
     var exe = EmbeddedExecutable{
-        .inner = builder.addExecutable(name, root_path ++ "core/microzig.zig"),
+        .inner = builder.addExecutable(.{ .name = name, .root_source_file = .{ .path = root_path ++ "core/microzig.zig" }, .target = chip.cpu.target, .optimize = options.optimize }),
         .app_packages = std.ArrayList(Pkg).init(builder.allocator),
     };
 
@@ -186,7 +183,6 @@ pub fn addEmbeddedExecutable(
     // might not be true for all machines (Pi Pico), but
     // for the HAL it's true (it doesn't know the concept of threading)
     exe.inner.single_threaded = true;
-    exe.inner.setTarget(chip.cpu.target);
 
     const linkerscript = LinkerScriptStep.create(builder, chip) catch unreachable;
     exe.inner.setLinkerScriptPath(.{ .generated = &linkerscript.generated_file });