diff --git a/artiq/firmware/ksupport/lib.rs b/artiq/firmware/ksupport/lib.rs
index 1a152849..967cb542 100644
--- a/artiq/firmware/ksupport/lib.rs
+++ b/artiq/firmware/ksupport/lib.rs
@@ -477,17 +477,11 @@ pub unsafe fn main() {
         }
     });
 
-    let __bss_start = library.lookup(b"__bss_start").unwrap();
-    let _end = library.lookup(b"_end").unwrap();
     let __modinit__ = library.lookup(b"__modinit__").unwrap();
     let typeinfo = library.lookup(b"typeinfo");
-    let _sstack_guard = library.lookup(b"_sstack_guard").unwrap();
 
     LIBRARY = Some(library);
 
-    ptr::write_bytes(__bss_start as *mut u8, 0, (_end - __bss_start) as usize);
-
-    board_misoc::pmp::init_stack_guard(_sstack_guard as usize);
     board_misoc::cache::flush_cpu_dcache();
     board_misoc::cache::flush_cpu_icache();