diff --git a/Cargo.toml b/Cargo.toml
index b8c240b..4d8109e 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -28,6 +28,8 @@ mutex-trait = "0.2"
 
 bare-metal = "1"
 
+# Only used for shell, where a macro is described to take a string literal and
+# in the macro implementation turns it into a CStr.
 cstr = "^0.2.11"
 
 heapless = "^0.8"
diff --git a/src/gcoap.rs b/src/gcoap.rs
index 4e530d0..8d90768 100644
--- a/src/gcoap.rs
+++ b/src/gcoap.rs
@@ -155,7 +155,7 @@ where
     /// [coap_handler::Handler], you can wrap it in [crate::coap_handler::GcoapHandler] to for adaptation.
     pub fn new_catch_all(handler: &'a mut H) -> Self {
         Self::new(
-            cstr::cstr!("/"),
+            c"/",
             riot_sys::COAP_GET
                 | riot_sys::COAP_POST
                 | riot_sys::COAP_PUT
diff --git a/src/gnrc/ipv6.rs b/src/gnrc/ipv6.rs
index d8d401a..2580533 100644
--- a/src/gnrc/ipv6.rs
+++ b/src/gnrc/ipv6.rs
@@ -215,7 +215,7 @@ impl<M: Mode> Pktsnip<M> {
         // unsafe: C API, and requirement on a Pktsnip that typed snips follow that type's
         // conventions
         let ptr = unsafe { riot_sys::gnrc_ipv6_get_header(self.ptr) };
-        if ptr == 0 as _ {
+        if ptr.is_null() {
             None
         } else {
             // unsafe: Header is a transparent wrapper around the actual ipv6_hdr_t, and the
diff --git a/src/gnrc/mod.rs b/src/gnrc/mod.rs
index 088edb8..0255226 100644
--- a/src/gnrc/mod.rs
+++ b/src/gnrc/mod.rs
@@ -47,7 +47,7 @@ impl Netif {
 
     #[doc(alias = "gnrc_netif_get_by_pid")]
     pub fn by_pid(pid: KernelPID) -> Option<Self> {
-        const NULL: *mut riot_sys::gnrc_netif_t = 0 as _;
+        const NULL: *mut riot_sys::gnrc_netif_t = core::ptr::null_mut();
         // Not using as_ref: We can't guarantee that even for the short period between we're making
         // it into a reference and casting it back to a pointer again, it is not used by anyone
         // else
diff --git a/src/gnrc_pktbuf.rs b/src/gnrc_pktbuf.rs
index 4d2aa47..5155c91 100644
--- a/src/gnrc_pktbuf.rs
+++ b/src/gnrc_pktbuf.rs
@@ -201,7 +201,7 @@ impl<'a> Pktsnip<Shared> {
         // unsafe: The C functions justify the new type
         unsafe {
             let new = riot_sys::gnrc_pktbuf_start_write(self.to_ptr());
-            if new == 0 as _ {
+            if new.is_null() {
                 Err(NotEnoughSpace)
             } else {
                 Ok(Pktsnip::<Writable>::from_ptr(new))
diff --git a/src/panic.rs b/src/panic.rs
index 688d5da..0176125 100644
--- a/src/panic.rs
+++ b/src/panic.rs
@@ -22,7 +22,7 @@ fn panic(info: &::core::panic::PanicInfo) -> ! {
         unsafe {
             riot_sys::core_panic(
                 riot_sys::core_panic_t_PANIC_GENERAL_ERROR,
-                cstr::cstr!("RUST PANIC").as_ptr() as _,
+                c"RUST PANIC".as_ptr() as _,
             )
         };
     } else {
diff --git a/src/saul/registration.rs b/src/saul/registration.rs
index cc2d22b..ba0e6bc 100644
--- a/src/saul/registration.rs
+++ b/src/saul/registration.rs
@@ -195,7 +195,7 @@ where
     ) -> Self {
         Registration {
             reg: riot_sys::saul_reg_t {
-                next: 0 as _,
+                next: core::ptr::null_mut(),
                 dev: device as *const _ as *mut _,
                 name: name.map(|n| n.as_ptr() as _).unwrap_or(core::ptr::null()),
                 driver: &driver.driver as *const _,
diff --git a/src/ztimer/periodic.rs b/src/ztimer/periodic.rs
index 0694990..13393b0 100644
--- a/src/ztimer/periodic.rs
+++ b/src/ztimer/periodic.rs
@@ -80,7 +80,7 @@ impl<H: Handler, const HZ: u32> Timer<H, HZ> {
                 clock.0,
                 timer.as_mut_ptr(),
                 Some(Self::callback),
-                0 as _,
+                core::ptr::null_mut(),
                 ticks.0,
             );
             timer.assume_init()