diff --git a/BUILDING.md b/BUILDING.md
index 3a2eae88..6dfeddb2 100644
--- a/BUILDING.md
+++ b/BUILDING.md
@@ -125,16 +125,18 @@ ARM, unlike Intel, does not have an instruction that allows applications to
 discover the capabilities of the processor. Instead, the capability information
 has to be provided by the operating system somehow.
 
-BoringSSL will try to use `getauxval` to discover the capabilities and, failing
-that, will probe for NEON support by executing a NEON instruction and handling
-any illegal-instruction signal. But some environments don't support that sort
-of thing and, for them, it's possible to configure the CPU capabilities
-at compile time.
-
-If you define `OPENSSL_STATIC_ARMCAP` then you can define any of the following
-to enabling the corresponding ARM feature.
-
-  * `OPENSSL_STATIC_ARMCAP_NEON` or `__ARM_NEON__` (note that the latter is set by compilers when NEON support is enabled).
+By default, on Linux-based systems, BoringSSL will try to use `getauxval` and
+`/proc` to discover the capabilities. But some environments don't support that
+sort of thing and, for them, it's possible to configure the CPU capabilities at
+compile time.
+
+On iOS or builds which define `OPENSSL_STATIC_ARMCAP`, features will be
+determined based on the `__ARM_NEON__` and `__ARM_FEATURE_CRYPTO` preprocessor
+symbols reported by the compiler. These values are usually controlled by the
+`-march` flag. You can also define any of the following to enable the
+corresponding ARM feature.
+
+  * `OPENSSL_STATIC_ARMCAP_NEON`
   * `OPENSSL_STATIC_ARMCAP_AES`
   * `OPENSSL_STATIC_ARMCAP_SHA1`
   * `OPENSSL_STATIC_ARMCAP_SHA256`
diff --git a/crypto/crypto.c b/crypto/crypto.c
index a52b8089..3e1765b8 100644
--- a/crypto/crypto.c
+++ b/crypto/crypto.c
@@ -73,16 +73,16 @@ uint32_t OPENSSL_armcap_P =
 #if defined(OPENSSL_STATIC_ARMCAP_NEON) || defined(__ARM_NEON__)
     ARMV7_NEON |
 #endif
-#if defined(OPENSSL_STATIC_ARMCAP_AES)
+#if defined(OPENSSL_STATIC_ARMCAP_AES) || defined(__ARM_FEATURE_CRYPTO)
     ARMV8_AES |
 #endif
-#if defined(OPENSSL_STATIC_ARMCAP_SHA1)
+#if defined(OPENSSL_STATIC_ARMCAP_SHA1) || defined(__ARM_FEATURE_CRYPTO)
     ARMV8_SHA1 |
 #endif
-#if defined(OPENSSL_STATIC_ARMCAP_SHA256)
+#if defined(OPENSSL_STATIC_ARMCAP_SHA256) || defined(__ARM_FEATURE_CRYPTO)
     ARMV8_SHA256 |
 #endif
-#if defined(OPENSSL_STATIC_ARMCAP_PMULL)
+#if defined(OPENSSL_STATIC_ARMCAP_PMULL) || defined(__ARM_FEATURE_CRYPTO)
     ARMV8_PMULL |
 #endif
     0;
diff --git a/include/openssl/cpu.h b/include/openssl/cpu.h
index 81cc5bad..5ccf14b8 100644
--- a/include/openssl/cpu.h
+++ b/include/openssl/cpu.h
@@ -156,7 +156,7 @@ static inline int CRYPTO_is_NEON_capable(void) {
 }
 
 static inline int CRYPTO_is_ARMv8_AES_capable(void) {
-#if defined(OPENSSL_STATIC_ARMCAP_AES)
+#if defined(OPENSSL_STATIC_ARMCAP_AES) || defined(__ARM_FEATURE_CRYPTO)
   return 1;
 #else
   return 0;
@@ -164,7 +164,7 @@ static inline int CRYPTO_is_ARMv8_AES_capable(void) {
 }
 
 static inline int CRYPTO_is_ARMv8_PMULL_capable(void) {
-#if defined(OPENSSL_STATIC_ARMCAP_PMULL)
+#if defined(OPENSSL_STATIC_ARMCAP_PMULL) || defined(__ARM_FEATURE_CRYPTO)
   return 1;
 #else
   return 0;