diff --git a/src/start.rs b/src/start.rs
--- a/src/start.rs
+++ b/src/start.rs
@@ -1,8 +1,6 @@
 //! Startup code.
 
 use alloc::{boxed::Box, vec::Vec};
-use core::{intrinsics, ptr};
-
-#[cfg(target_os = "redox")]
-use generic_rt::ExpectTlsFree;
+use core::{fmt::Write, intrinsics, panic::AssertUnwindSafe, ptr};
 
 use crate::{
     ALLOCATOR,
@@ -143,6 +141,28 @@ fn io_init() {
         stdio::stderr = stdio::default_stderr().get();
     }
 }
+
+fn catch_unwind<F: FnOnce()>(f: AssertUnwindSafe<F>) -> Result<(), ()> {
+    fn do_call<F: FnOnce()>(data: *mut u8) {
+        let callback = unsafe { &mut *data.cast::<Option<AssertUnwindSafe<F>>>() };
+        if let Some(callback) = callback.take() {
+            callback.0();
+        }
+    }
+
+    fn do_catch<F: FnOnce()>(_data: *mut u8, _payload: *mut u8) {}
+
+    let mut callback = Some(f);
+    let panicked = unsafe {
+        intrinsics::catch_unwind(
+            do_call::<F>,
+            (&mut callback as *mut Option<AssertUnwindSafe<F>>).cast(),
+            do_catch::<F>,
+        ) != 0
+    };
+
+    if panicked { Err(()) } else { Ok(()) }
+}
+
 #[cold]
 fn abort_startup(args: core::fmt::Arguments<'_>) -> ! {
     let mut w = platform::FileWriter::new(2);
@@ -164,15 +184,24 @@ pub unsafe extern "C" fn relibc_start_v1(
     unsafe { relibc_verify_host() };
 
     #[cfg(target_os = "redox")]
-    let thr_fd = redox_rt::proc::FdGuard::new(
-        unsafe {
-            crate::platform::get_auxv_raw(sp.auxv().cast(), redox_rt::auxv_defs::AT_REDOX_THR_FD)
-        }
-        .expect_notls("no thread fd present"),
-    )
-    .to_upper()
-    .expect_notls("failed to move thread fd to upper table");
+    let thr_fd = {
+        let thr_fd = match unsafe {
+            crate::platform::get_auxv_raw(sp.auxv().cast(), redox_rt::auxv_defs::AT_REDOX_THR_FD)
+        } {
+            Some(thr_fd) => thr_fd,
+            None => abort_startup(format_args!(
+                "relibc_start_v1: missing AT_REDOX_THR_FD auxv entry; no thread fd present\n"
+            )),
+        };
+
+        match redox_rt::proc::FdGuard::new(thr_fd).to_upper() {
+            Ok(thr_fd) => thr_fd,
+            Err(err) => abort_startup(format_args!(
+                "relibc_start_v1: failed to move thread fd to upper table: {err:?}\n"
+            )),
+        }
+    };
 
     // Initialize TLS, if necessary
     unsafe {
@@ -237,7 +266,10 @@ pub unsafe extern "C" fn relibc_start_v1(
         let mut f = unsafe { &__preinit_array_start } as *const _;
         #[allow(clippy::op_ref)]
         while f < &raw const __preinit_array_end {
-            (unsafe { *f })();
+            let func = unsafe { *f };
+            if catch_unwind(AssertUnwindSafe(|| unsafe { (*f)() })).is_err() {
+                log_initializer_panic(".preinit_array", func);
+            }
             f = unsafe { f.offset(1) };
         }
     }
@@ -247,7 +279,10 @@ pub unsafe extern "C" fn relibc_start_v1(
         let mut f = unsafe { &__init_array_start } as *const _;
         #[allow(clippy::op_ref)]
         while f < &raw const __init_array_end {
-            (unsafe { *f })();
+            let func = unsafe { *f };
+            if catch_unwind(AssertUnwindSafe(|| unsafe { (*f)() })).is_err() {
+                log_initializer_panic(".init_array", func);
+            }
             f = unsafe { f.offset(1) };
         }
     }