diff --git a/apis/buttons/src/lib.rs b/apis/buttons/src/lib.rs
index 565970f..f5d08b5 100644
--- a/apis/buttons/src/lib.rs
+++ b/apis/buttons/src/lib.rs
@@ -135,7 +135,7 @@ mod tests;
 // Driver number and command IDs
 // -----------------------------------------------------------------------------
 
-const DRIVER_NUM: u32 = 3;
+pub const DRIVER_NUM: u32 = 3;
 
 // Command IDs
 const BUTTONS_COUNT: u32 = 0;
diff --git a/runtime/Cargo.toml b/runtime/Cargo.toml
index a863392..3509a40 100644
--- a/runtime/Cargo.toml
+++ b/runtime/Cargo.toml
@@ -14,6 +14,9 @@ libtock_platform = { path = "../platform" }
 
 [features]
 
+# Initialize an allocator for access to heap memory
+alloc_init = []
+
 # By default, libtock_runtime looks for the LIBTOCK_PLATFORM variable to decide
 # what layout file to use. If you are providing your own linker script, set
 # no_auto_layout to disable the layout file logic.
diff --git a/runtime/src/lib.rs b/runtime/src/lib.rs
index 1054e41..b5c519a 100644
--- a/runtime/src/lib.rs
+++ b/runtime/src/lib.rs
@@ -19,6 +19,7 @@
 //! and provide its own layout file.
 
 #![no_std]
+#![feature(strict_provenance)]
 #![warn(unsafe_op_in_unsafe_fn)]
 
 pub mod startup;
diff --git a/runtime/src/startup/mod.rs b/runtime/src/startup/mod.rs
index 769bfe9..052479f 100644
--- a/runtime/src/startup/mod.rs
+++ b/runtime/src/startup/mod.rs
@@ -10,6 +10,8 @@ core::arch::global_asm!(include_str!("asm_arm.s"));
 #[cfg(target_arch = "riscv32")]
 core::arch::global_asm!(include_str!("asm_riscv32.s"));
 
+static APP_HEAP_SIZE: Option<&'static str> = option_env!("APP_HEAP_SIZE");
+
 /// `set_main!` is used to tell `libtock_runtime` where the process binary's
 /// `main` function is. The process binary's `main` function must have the
 /// signature `FnOnce() -> T`, where T is some concrete type that implements
@@ -83,6 +85,8 @@ extern "C" fn rust_start() -> ! {
     extern "Rust" {
         fn libtock_unsafe_main() -> !;
         static rt_header: RtHeader;
+        #[cfg(feature = "alloc_init")]
+        fn libtock_alloc_init(heap_bottom: *mut u8, heap_size: usize);
     }
 
     // TODO: Implement a safe memop API in libtock_platform and migrate these
@@ -92,16 +96,46 @@ extern "C" fn rust_start() -> ! {
     // impact the execution of this process.
     #[cfg(not(feature = "no_debug_memop"))]
     unsafe {
+        // specify the top of the application stack which grows downwards
         TockSyscalls::syscall2::<{ syscall_class::MEMOP }>([
             10u32.into(),
             rt_header.stack_top.into(),
         ]);
+
+        // specify the start of the application heap which grows upwards
         TockSyscalls::syscall2::<{ syscall_class::MEMOP }>([
             11u32.into(),
             rt_header.initial_break.into(),
         ]);
     }
 
+    #[cfg(feature = "alloc_init")]
+    {
+        let app_heap_size: usize = match APP_HEAP_SIZE {
+            Some(var) => var
+                .parse()
+                .ok()
+                .expect("could not parse APP_HEAP_SIZE as usize!"),
+            None => 9000,
+        };
+
+        // the heap starts after the `bss` section
+        let app_heap_bottom = unsafe { rt_header.bss_start.add(rt_header.bss_size) };
+
+        assert_eq!(app_heap_bottom.addr(), unsafe {
+            rt_header.bss_start.addr() + rt_header.bss_size
+        });
+
+        let app_heap_end = unsafe { app_heap_bottom.add(app_heap_size) };
+
+        unsafe {
+            // tell the kernel the new app heap break (which is the upper address bound of the process)
+            TockSyscalls::syscall2::<{ syscall_class::MEMOP }>([0u32.into(), app_heap_end.into()]);
+
+            libtock_alloc_init(app_heap_bottom, app_heap_size);
+        }
+    }
+
     // Safety: libtock_unsafe_main is defined by the set_main! macro, and its
     // signature matches the signature in the `extern` block in this function.
     unsafe {
diff --git a/rust-toolchain b/rust-toolchain
index e911a96..d139e12 100644
--- a/rust-toolchain
+++ b/rust-toolchain
@@ -1,7 +1,7 @@
 [toolchain]
 # See https://rust-lang.github.io/rustup-components-history/ for a list of
 # recently nightlies and what components are available for them.
-channel = "nightly-2022-06-10"
+channel = "nightly-2023-02-01"
 components = ["clippy", "miri", "rustfmt"]
 targets = ["thumbv7em-none-eabi",
            "riscv32imac-unknown-none-elf",