diff --git a/src/ccan/ccan/compiler/compiler.h b/src/ccan/ccan/compiler/compiler.h
index bce4f25a1..4342fe18b 100644
--- a/src/ccan/ccan/compiler/compiler.h
+++ b/src/ccan/ccan/compiler/compiler.h
@@ -228,4 +228,16 @@
 #define WARN_UNUSED_RESULT
 #endif
 #endif
+
+/* ALIGNED - ensure a structure/variable is aligned to a given number of bytes
+ *
+ */
+#ifndef ALIGNED
+#if (defined(__clang__) || defined(__GNUC__))
+#define ALIGNED(N) __attribute__((aligned(N)))
+#else
+#define ALIGNED(N)
+#endif
+#endif /* ALIGNED */
+
 #endif /* CCAN_COMPILER_H */
diff --git a/src/ccan/ccan/crypto/sha256/sha256.c b/src/ccan/ccan/crypto/sha256/sha256.c
index 6f3c5478c..582b40f16 100644
--- a/src/ccan/ccan/crypto/sha256/sha256.c
+++ b/src/ccan/ccan/crypto/sha256/sha256.c
@@ -59,6 +59,7 @@ inline void sha256_update(struct sha256_ctx *ctx, const void *p, size_t size)
 inline void sha256_done(struct sha256_ctx *ctx, struct sha256* res)
 {
 	mbedtls_sha256_finish(&ctx->c, res->u.u8);
+	mbedtls_sha256_free(&ctx->c);
 }
 void sha256_optimize(void)
 {
diff --git a/src/ccan/ccan/crypto/sha256/sha256_sse4.c b/src/ccan/ccan/crypto/sha256/sha256_sse4.c
index 8ead1dbf6..7eb32fca9 100644
--- a/src/ccan/ccan/crypto/sha256/sha256_sse4.c
+++ b/src/ccan/ccan/crypto/sha256/sha256_sse4.c
@@ -9,9 +9,6 @@
 #include <stdlib.h>
 
 #if defined(__x86_64__) || defined(__amd64__)
-/* TODO: Support alignment in compiler.h */
-#define ALIGNED(N) __attribute__((aligned(N)))
-
 void TransformSSE4(uint32_t* s, const uint32_t* chunk, size_t blocks)
 {
     static const uint32_t K256[] ALIGNED(16) = {
diff --git a/src/ccan/ccan/crypto/sha512/sha512.c b/src/ccan/ccan/crypto/sha512/sha512.c
index 3811357fc..a8629bc99 100644
--- a/src/ccan/ccan/crypto/sha512/sha512.c
+++ b/src/ccan/ccan/crypto/sha512/sha512.c
@@ -15,28 +15,19 @@
 #endif
 #include <string.h>
 
+#ifdef CCAN_CRYPTO_SHA512_USE_OPENSSL
 static void invalidate_sha512(struct sha512_ctx *ctx)
 {
-#ifdef CCAN_CRYPTO_SHA512_USE_OPENSSL
 	ctx->c.md_len = 0;
-#elif defined(CCAN_CRYPTO_SHA512_USE_MBEDTLS)
-#else
-	ctx->bytes = (size_t)-1;
-#endif
 }
 
 static void check_sha512(struct sha512_ctx *ctx UNUSED)
 {
 #if 0
-#ifdef CCAN_CRYPTO_SHA512_USE_OPENSSL
 	assert(ctx->c.md_len != 0);
-#else
-	assert(ctx->bytes != (size_t)-1);
-#endif
 #endif
 }
 
-#ifdef CCAN_CRYPTO_SHA512_USE_OPENSSL
 void sha512_init(struct sha512_ctx *ctx)
 {
 	SHA512_Init(&ctx->c);
@@ -62,16 +53,27 @@ inline void sha512_init(struct sha512_ctx *ctx)
 
 inline void sha512_update(struct sha512_ctx *ctx, const void *p, size_t size)
 {
-	check_sha512(ctx);
 	mbedtls_sha512_update(&ctx->c, p, size);
 }
 
 inline void sha512_done(struct sha512_ctx *ctx, struct sha512* res)
 {
 	mbedtls_sha512_finish(&ctx->c, res->u.u8);
-	invalidate_sha512(ctx);
+	mbedtls_sha512_free(&ctx->c);
 }
 #else
+static void invalidate_sha512(struct sha512_ctx *ctx)
+{
+	ctx->bytes = (size_t)-1;
+}
+
+static void check_sha512(struct sha512_ctx *ctx UNUSED)
+{
+#if 0
+	assert(ctx->bytes != (size_t)-1);
+#endif
+}
+
 static uint64_t Ch(uint64_t x, uint64_t y, uint64_t z)
 {
 	return z ^ (x & (y ^ z));
diff --git a/src/tx_io.c b/src/tx_io.c
index aea93e988..fb170a0fb 100644
--- a/src/tx_io.c
+++ b/src/tx_io.c
@@ -10,6 +10,16 @@
 
 #define SIGTYPE_ALL (WALLY_SIGTYPE_PRE_SW | WALLY_SIGTYPE_SW_V0 | WALLY_SIGTYPE_SW_V1)
 
+#if defined(CCAN_CRYPTO_SHA256_USE_OPENSSL) || defined(CCAN_CRYPTO_SHA256_USE_MBEDTLS)
+/* For external sha256 implementations, we cannot cache the sha256 context as
+ * they require extra setup before use that only sha256_init() provides.
+ */
+#define TXIO_CTX_CACHEABLE 0
+#else
+/* For our built-in sha256 implementation we can cache and use the context */
+#define TXIO_CTX_CACHEABLE 1
+#endif
+
 /* Cache keys for data that is constant while signing a given tx.
  * We also cache other data keyed by their binary value directly.
  */
@@ -761,12 +771,14 @@ static int bip143_signature_hash(
 static void txio_bip341_init(cursor_io *io,
                              const unsigned char *genesis_blockhash, size_t genesis_blockhash_len)
 {
-    const struct wally_map_item *item;
-    item = io->cache ? wally_map_get_integer(io->cache, TXIO_SHA_TAPSIGHASH_CTX) : NULL;
-    if (item) {
-        /* Note we hash the intial sha256_ctx itself here and so memcpy it */
-        memcpy(&io->ctx, item->value, item->value_len);
-        return;
+    if (TXIO_CTX_CACHEABLE && io->cache) {
+        const struct wally_map_item *item = NULL;
+        item = wally_map_get_integer(io->cache, TXIO_SHA_TAPSIGHASH_CTX);
+        if (item) {
+            /* Note we cached the intial sha256_ctx itself here and so memcpy it */
+            memcpy(&io->ctx, item->value, item->value_len);
+            return;
+        }
     }
 
     tagged_hash_init(&io->ctx, TAPSIGHASH_SHA256(genesis_blockhash != NULL), SHA256_LEN);
@@ -774,7 +786,7 @@ static void txio_bip341_init(cursor_io *io,
         hash_bytes(&io->ctx, genesis_blockhash, genesis_blockhash_len);
         hash_bytes(&io->ctx, genesis_blockhash, genesis_blockhash_len);
     }
-    if (io->cache)
+    if (TXIO_CTX_CACHEABLE && io->cache)
         wally_map_add_integer(io->cache, TXIO_SHA_TAPSIGHASH_CTX,
                               (const unsigned char*)&io->ctx, sizeof(io->ctx));
 }