diff --git a/.travis.yml b/.travis.yml
index 651ad97..dae25d0 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -7,7 +7,7 @@
 
 language: rust
 rust:
-  - nightly-2019-11-06
+  - nightly-2020-01-16
 
 os:
   - linux
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 68c463d..1caeca5 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -45,6 +45,7 @@
 [      OK ] Dynamic dispatch
 [      OK ] Formatting
 [      OK ] Heap
+[      OK ] Drivers only instantiable once
 [      OK ] Callbacks
 [      OK ] GPIO initialization
 [      OK ] GPIO activation
diff --git a/codegen/src/lib.rs b/codegen/src/lib.rs
index 6f51b9f..9804e29 100644
--- a/codegen/src/lib.rs
+++ b/codegen/src/lib.rs
@@ -5,7 +5,6 @@
 use proc_macro::TokenStream;
 
 use quote::quote;
-use syn;
 use syn::Error;
 use syn::ItemFn;
 
diff --git a/examples-alloc/libtock_test.rs b/examples-alloc/libtock_test.rs
index d764af3..26cccb4 100644
--- a/examples-alloc/libtock_test.rs
+++ b/examples-alloc/libtock_test.rs
@@ -46,6 +46,7 @@
     test.dynamic_dispatch()?;
     test.formatting()?;
     test.heap()?;
+    test.drivers_only_instantiable_once()?;
     test.callbacks(timer).await?;
     test.gpio(gpio)?;
     Ok(())
@@ -100,6 +101,13 @@
         self.check_if_true(string == "foobar", "Heap")
     }
 
+    fn drivers_only_instantiable_once(&mut self) -> TockResult<()> {
+        self.check_if_true(
+            libtock::retrieve_drivers().is_err(),
+            "Drivers only instantiable once",
+        )
+    }
+
     async fn callbacks(&mut self, timer_context: &mut DriverContext) -> TockResult<()> {
         let mut callback_hit = false;
         let mut with_callback = timer_context.with_callback(|_, _| callback_hit = true);
diff --git a/flash.sh b/flash.sh
index a67312c..b241a7a 100755
--- a/flash.sh
+++ b/flash.sh
@@ -4,8 +4,36 @@
 
 artifact="$(basename $1)"
 rust_target_folder="$(readlink -f $(dirname $1)/../..)"
+
+case "${PLATFORM}" in
+    "nrf52"|"nrf52840")
+        tockloader_flags="--jlink --arch cortex-m4 --board nrf52dk --jtag-device nrf52"
+        binary_name=cortex-m4.elf
+        tockload=y
+        ;;
+    "hail")
+        tockloader_flags=""
+        binary_name=cortex-m4.elf
+        tockload=y
+        ;;
+    "riscv32")
+        tockloader_flags=""
+        binary_name=rv32imac.elf
+        tockload=n
+        ;;
+    "opentitan")
+        tockloader_flags=""
+        binary_name=rv32imc.elf
+        tockload=n
+        ;;
+    *)
+        echo "Unknown platform \"${PLATFORM}\""
+        exit 1
+        ;;
+esac
+
 libtock_target_path="${rust_target_folder}/tab/${PLATFORM}/${artifact}"
-elf_file_name="${libtock_target_path}/cortex-m4.elf"
+elf_file_name="${libtock_target_path}/${binary_name}"
 tab_file_name="${libtock_target_path}.tab"
 
 mkdir -p "${libtock_target_path}"
@@ -13,18 +41,10 @@
 
 elf2tab -n "${artifact}" -o "${tab_file_name}" "${elf_file_name}" --stack 2048 --app-heap 1024 --kernel-heap 1024 --protected-region-size=64
 
-case "${PLATFORM}" in
-    "nrf52"|"nrf52840")
-        tockloader_flags="--jlink --arch cortex-m4 --board nrf52dk --jtag-device nrf52"
-        ;;
-    "hail")
-        tockloader_flags=""
-        ;;
-    *)
-        echo "Tockloader flags unknown for platform \"${PLATFORM}\""
-        exit 1
-        ;;
-esac
+if [ $tockload == "n" ]; then
+	echo "Skipping flashing for platform \"${PLATFORM}\""
+	exit 0
+fi
 
 tockloader uninstall ${tockloader_flags} || true
 tockloader install ${tockloader_flags} "${tab_file_name}"
diff --git a/layout_generic.ld b/layout_generic.ld
index 6b96ee5..35b10f4 100644
--- a/layout_generic.ld
+++ b/layout_generic.ld
@@ -86,7 +86,7 @@
     } > FLASH =0xFF
 
     /* Application stack */
-    .stack :
+    .stack (NOLOAD) :
     {
         . = . + STACK_SIZE;
 
diff --git a/layout_opentitan.ld b/layout_opentitan.ld
index ab475fc..db48eef 100644
--- a/layout_opentitan.ld
+++ b/layout_opentitan.ld
@@ -1,9 +1,16 @@
 /* Layout for the RISC-V 32 boards, used by the examples in this repository. */
 
 MEMORY {
-  /* The TBF header region is 32 bytes (0x20) */
-  FLASH (rx) : ORIGIN = 0x20030020, LENGTH = 32M
-  SRAM (rwx) : ORIGIN = 0x10000000, LENGTH = 512K
+  /*
+   * The TBF header can change in size so use 0x40 combined with
+   * --protected-region-size with elf2tab to cover a header upto that
+   * size.
+   *
+   * Note that the SRAM address may need to be changed depending on
+   * the kernel binary, check for the actual address of APP_MEMORY!
+   */
+  FLASH (rx) : ORIGIN = 0x20030040, LENGTH = 32M
+  SRAM (rwx) : ORIGIN = 0x10002800, LENGTH = 512K
 }
 
 /*
diff --git a/layout_riscv32.ld b/layout_riscv32.ld
index e3aba2c..df7d4b6 100644
--- a/layout_riscv32.ld
+++ b/layout_riscv32.ld
@@ -1,9 +1,16 @@
 /* Layout for the RISC-V 32 boards, used by the examples in this repository. */
 
 MEMORY {
-  /* The TBF header region is 32 bytes (0x20) */
-  FLASH (rx) : ORIGIN = 0x20430020, LENGTH = 32M
-  SRAM (rwx) : ORIGIN = 0x80000000, LENGTH = 512K
+  /*
+   * The TBF header can change in size so use 0x40 combined with
+   * --protected-region-size with elf2tab to cover a header upto that
+   * size.
+   *
+   * Note that the SRAM address may need to be changed depending on
+   * the kernel binary, check for the actual address of APP_MEMORY!
+   */
+  FLASH (rx) : ORIGIN = 0x20430040, LENGTH = 32M
+  SRAM (rwx) : ORIGIN = 0x80002400, LENGTH = 512K
 }
 
 /*
diff --git a/run_all_checks.sh b/run_all_checks.sh
index c445608..3dde5ff 100755
--- a/run_all_checks.sh
+++ b/run_all_checks.sh
@@ -5,6 +5,6 @@
 export PLATFORM=nrf52 # The specific platform doesn't matter for tests
 
 cargo fmt --all -- --check
-cargo test --workspace
 cargo clippy --workspace --all-targets
+cargo test --workspace
 ./build_examples.sh
diff --git a/rust-toolchain b/rust-toolchain
index 22e9048..20d9cda 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1 +1 @@
-nightly-2019-11-06
+nightly-2020-01-16
diff --git a/src/drivers.rs b/src/drivers.rs
index a8e1e98..4e7eff8 100644
--- a/src/drivers.rs
+++ b/src/drivers.rs
@@ -38,9 +38,15 @@
 
 /// Retrieve [Drivers] struct. Returns struct only once.
 pub fn retrieve_drivers() -> TockResult<Drivers> {
-    match unsafe { DRIVERS_SINGLETON.take() } {
-        Some(drivers) => Ok(drivers),
-        None => Err(TockError::Other(OtherError::DriverAlreadyTaken)),
+    static mut DRIVER_TAKEN: bool = false;
+
+    unsafe {
+        if DRIVER_TAKEN {
+            Err(TockError::Other(OtherError::DriverAlreadyTaken))
+        } else {
+            DRIVER_TAKEN = true;
+            Ok(retrieve_drivers_unsafe())
+        }
     }
 }
 
@@ -73,24 +79,3 @@
     humidity_sensor: HumiditySensor,
     ninedof: NinedofDriver,
 };
-
-static mut DRIVERS_SINGLETON: Option<Drivers> = Some(DRIVERS);
-
-#[cfg(test)]
-mod test {
-    use super::*;
-
-    #[test]
-    pub fn can_be_retrieved_once() {
-        reset_drivers_singleton();
-
-        assert!(retrieve_drivers().is_ok());
-        assert!(retrieve_drivers().is_err());
-    }
-
-    fn reset_drivers_singleton() {
-        unsafe {
-            DRIVERS_SINGLETON = Some(DRIVERS);
-        };
-    }
-}
diff --git a/src/lang_items.rs b/src/lang_items.rs
index b8731a2..9c301eb 100644
--- a/src/lang_items.rs
+++ b/src/lang_items.rs
@@ -27,11 +27,12 @@
 use core::panic::PanicInfo;
 
 #[lang = "start"]
-extern "C" fn start<T>(main: fn() -> T, _argc: isize, _argv: *const *const u8)
+extern "C" fn start<T>(main: fn() -> T, _argc: isize, _argv: *const *const u8) -> bool
 where
     T: Termination,
 {
     main().check_result();
+    true // Need to return anything sized. Otherwise, a linker error pops up. (See https://github.com/tock/libtock-rs/issues/138)
 }
 
 #[lang = "termination"]