diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7b61fc8..fc5f3fa 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -43,7 +43,7 @@ file(GLOB photon_libc_crt
     ${CMAKE_CURRENT_SOURCE_DIR}/photon/libc/sys/${platform}/machine/${machine}/crt*.s)
 
 add_library(crt OBJECT ${photon_libc_crt})
-target_compile_options(crt PRIVATE -c)
+target_compile_options(crt PRIVATE -c -ffreestanding -nostdlib)
 
 file(GLOB platform_sources
     ${CMAKE_CURRENT_SOURCE_DIR}/photon/libc/sys/${platform}/*.c
diff --git a/photon/libc/sys/magenta/machine/x86_64/crt0.s b/photon/libc/sys/magenta/machine/x86_64/crt0.s
index 90e0b6d..375b84c 100644
--- a/photon/libc/sys/magenta/machine/x86_64/crt0.s
+++ b/photon/libc/sys/magenta/machine/x86_64/crt0.s
@@ -11,7 +11,8 @@ _start:
     mov %rsp, %rsi
     andq $-16, %rsp
     call __crt_init
-    movq %rax, %rsi
-    movq $1, %rdi /* MX_EXIT_ALL_THREADS */
-    movq $1, %rax /* mx_exit() */
+    movq %rax, %rdx
+    movq $1, %rsi /* MX_EXIT_ALL_THREADS */
+    movq $0, %rdi /* MX_NULL_HANDLE */
+    movq $23, %rax /* mx_process_kill() */
     syscall