diff --git a/bofs/src/wDirectSyscall.asm b/bofs/src/wDirectSyscall.asm
index e232f30..dc5bd21 100644
--- a/bofs/src/wDirectSyscall.asm
+++ b/bofs/src/wDirectSyscall.asm
@@ -8,7 +8,7 @@ section '.text' code readable executable align 8
 align 8
 go:
 .STACK_SIZE = 128+8
-    sub	rsp, .STACK_SIZE ; allocate some stack space and align it to 16 bytes
+    sub	rsp, .STACK_SIZE ; allocate stack space and align it to 16 bytes
 
     mov rax, [gs:0x60] ; PEB address
     mov rax, [rax+32] ; ProcessParameters address
@@ -28,13 +28,13 @@ go:
     mov dword [rsp+80], 0 ; EaLength
     call nt_create_file
 
-    mov ecx, 0
-    mov rdx, str_fmt
-    mov r8d, eax
-    call BeaconPrintf
+    mov ecx, 0 ; `type`
+    mov rdx, str_fmt ; `fmt`
+    mov r8d, eax ; `...`
+    call BeaconPrintf ; print result returned from syscall (NTSTATUS)
 
     add rsp, .STACK_SIZE
-    xor eax, eax
+    xor eax, eax ; BOF exit code
     ret
 
 ; syscall numbers for Windows 10+ x64:
diff --git a/build.zig b/build.zig
index 3d019d3..27e1449 100644
--- a/build.zig
+++ b/build.zig
@@ -139,12 +139,14 @@ pub fn build(b: *std.build.Builder) void {
         );
         winver_x86.step.dependOn(b.getInstallStep());
 
-        // TODO: Check if we are running on Windows 10+
-        //const direct_syscall_x64 = b.addSystemCommand(
-        //    &.{ "zig-out/bin/cli4bofs_win_x64.exe", "zig-out/bin/wDirectSyscall.coff.x64.o" },
-        //);
-        //direct_syscall_x64.step.dependOn(b.getInstallStep());
-        //test_step.dependOn(&direct_syscall_x64.step);
+        const detected_version = std.zig.system.windows.detectRuntimeVersion();
+        if (detected_version.isAtLeast(.win10)) {
+            const direct_syscall_x64 = b.addSystemCommand(
+                &.{ "zig-out/bin/cli4bofs_win_x64.exe", "zig-out/bin/wDirectSyscall.coff.x64.o" },
+            );
+            direct_syscall_x64.step.dependOn(b.getInstallStep());
+            test_step.dependOn(&direct_syscall_x64.step);
+        }
 
         test_step.dependOn(&udp_scanner_x64.step);
         test_step.dependOn(&udp_scanner_x86.step);