diff --git a/crates/llvm-context/Cargo.toml b/crates/llvm-context/Cargo.toml
index 715e3363..c3b8dd10 100644
--- a/crates/llvm-context/Cargo.toml
+++ b/crates/llvm-context/Cargo.toml
@@ -15,7 +15,12 @@ doctest = false
 
 [features]
 riscv-zbb = []
-riscv-64 = []
+riscv-64 = [
+    "revive-linker/riscv-64",
+    "revive-builtins/riscv-64",
+    "revive-runtime-api/riscv-64",
+    "revive-common/riscv-64",
+]
 
 [dependencies]
 anyhow = { workspace = true }
diff --git a/crates/llvm-context/src/polkavm/context/mod.rs b/crates/llvm-context/src/polkavm/context/mod.rs
index 7b41346d..bf39ded9 100644
--- a/crates/llvm-context/src/polkavm/context/mod.rs
+++ b/crates/llvm-context/src/polkavm/context/mod.rs
@@ -138,7 +138,7 @@ where
         for import in revive_runtime_api::polkavm_imports::IMPORTS {
             module
                 .get_function(import)
-                .expect("should be declared")
+                .unwrap_or_else(|| panic!("{import} import should be declared"))
                 .set_linkage(inkwell::module::Linkage::External);
         }
     }
diff --git a/crates/runtime-api/build.rs b/crates/runtime-api/build.rs
index 6559e579..6e801a02 100644
--- a/crates/runtime-api/build.rs
+++ b/crates/runtime-api/build.rs
@@ -11,9 +11,9 @@ const TARGET_FLAG: &str = "--target=riscv32";
 const TARGET_FLAG: &str = "--target=riscv64";
 
 #[cfg(not(feature = "riscv-64"))]
-const TARGET_ARCH_FLAG: &str = "-march=rv32em";
+const TARGET_ARCH_FLAG: &str = "-march=rv32emac";
 #[cfg(feature = "riscv-64")]
-const TARGET_ARCH_FLAG: &str = "-march=rv64em";
+const TARGET_ARCH_FLAG: &str = "-march=rv64emac";
 
 #[cfg(not(feature = "riscv-64"))]
 const TARGET_ABI_FLAG: &str = "-mabi=ilp32e";
@@ -36,6 +36,10 @@ fn compile(source_path: &str, bitcode_path: &str) {
             TARGET_TRIPLE_FLAG,
             TARGET_ARCH_FLAG,
             TARGET_ABI_FLAG,
+            "-Xclang",
+            "-target-feature",
+            "-Xclang",
+            "+fast-unaligned-access,+xtheadcondmov",
             "-fno-exceptions",
             "-ffreestanding",
             "-Wall",
diff --git a/crates/runtime-api/src/polkavm_guest.h b/crates/runtime-api/src/polkavm_guest.h
index 51767e38..1aa91f66 100644
--- a/crates/runtime-api/src/polkavm_guest.h
+++ b/crates/runtime-api/src/polkavm_guest.h
@@ -9,7 +9,11 @@
 
 #define POLKAVM_REGS_FOR_TY_void 0
 #define POLKAVM_REGS_FOR_TY_i32 1
-#define POLKAVM_REGS_FOR_TY_i64 2
+#ifdef _LP64
+    #define POLKAVM_REGS_FOR_TY_i64 1
+#else
+    #define POLKAVM_REGS_FOR_TY_i64 2
+#endif
 
 #define POLKAVM_REGS_FOR_TY_int8_t    POLKAVM_REGS_FOR_TY_i32
 #define POLKAVM_REGS_FOR_TY_uint8_t   POLKAVM_REGS_FOR_TY_i32
@@ -107,6 +111,26 @@ struct PolkaVM_Metadata {
     unsigned char output_regs;
 } __attribute__ ((packed));
 
+#ifdef _LP64
+    #define POLKAVM_EXPORT_DEF()  \
+        ".quad %[metadata]\n" \
+        ".quad %[function]\n"
+#else
+    #define POLKAVM_EXPORT_DEF()  \
+        ".word %[metadata]\n" \
+        ".word %[function]\n"
+#endif
+
+#ifdef _LP64
+    #define POLKAVM_IMPORT_DEF()  \
+        ".word 0x0000000b\n" \
+        ".quad %[metadata]\n"
+#else
+    #define POLKAVM_IMPORT_DEF()  \
+        ".word 0x0000000b\n" \
+        ".word %[metadata]\n"
+#endif
+
 #define POLKAVM_EXPORT(arg_return_ty, fn_name, ...) \
 static struct PolkaVM_Metadata POLKAVM_JOIN(fn_name, __EXPORT_METADATA) __attribute__ ((section(".polkavm_metadata"))) = { \
     1, 0, sizeof(#fn_name) - 1, #fn_name, POLKAVM_COUNT_REGS(__VA_ARGS__), POLKAVM_COUNT_REGS(arg_return_ty) \
@@ -115,8 +139,7 @@ static void __attribute__ ((naked, used)) POLKAVM_UNIQUE(polkavm_export_dummy)()
     __asm__( \
         ".pushsection .polkavm_exports,\"R\",@note\n" \
         ".byte 1\n" \
-        ".word %[metadata]\n" \
-        ".word %[function]\n" \
+        POLKAVM_EXPORT_DEF() \
         ".popsection\n" \
         : \
         : \
@@ -130,10 +153,9 @@ static void __attribute__ ((naked, used)) POLKAVM_UNIQUE(polkavm_export_dummy)()
 static struct PolkaVM_Metadata POLKAVM_JOIN(fn_name, __IMPORT_METADATA) __attribute__ ((section(".polkavm_metadata"))) = { \
     1, 0, sizeof(#fn_name) - 1, #fn_name, POLKAVM_COUNT_REGS(__VA_ARGS__), POLKAVM_COUNT_REGS(arg_return_ty) \
 }; \
-static arg_return_ty __attribute__ ((naked, used)) fn_name(POLKAVM_IMPORT_ARGS_IMPL(__VA_ARGS__)) { \
+static arg_return_ty __attribute__ ((used, naked)) fn_name(POLKAVM_IMPORT_ARGS_IMPL(__VA_ARGS__)) { \
     __asm__( \
-        ".word 0x0000000b\n" \
-        ".word %[metadata]\n" \
+        POLKAVM_IMPORT_DEF() \
         "ret\n" \
         : \
         : \