diff --git a/CHANGELOG.md b/CHANGELOG.md
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,24 @@
 # CHANGELOG for crypton
 
+## 2.0.1
+
+* fix(cpu): stop reading Intel's SDBG bit as AMD's XOP, which crashed SHA-512
+  and ChaCha20 on Broadwell and later.  The vendored assembly dispatches on a
+  capability word this library fills, and reads bit 11 of its second dword as
+  XOP -- which is CPUID leaf 0x80000001 ECX bit 11, an AMD extended leaf.
+  crypton put the raw leaf 1 ECX there, whose bit 11 is SDBG, the silicon
+  debug interface, which Intel has reported since Broadwell.  On such a
+  processor `sha512-x86_64.S` took `.Lxop_shortcut` and
+  `chacha-x86_64.S` took `.Lcrypton_chacha20_asm_4xop`, and the first
+  `vprotq` is an invalid opcode: SIGILL, for SHA-512 and SHA-384, and for
+  ChaCha20 and so ChaCha20-Poly1305.  OpenSSL clears leaf 1's bit 11 before
+  merging the real flag in; crypton now clears it and leaves it clear, so the
+  XOP paths are never taken.  Nothing is lost -- XOP ran from AMD's Bulldozer
+  to Excavator and Zen dropped it -- and it is the reason the AVX-512 bits
+  beside it are cleared as well.  Reported by @lucasdicioccio, who
+  disassembled the trap
+  [#202](https://github.com/kazu-yamamoto/crypton/issues/202)
+
 ## 2.0.0
 
 * fix(docs): export the names the documentation already referred to.
diff --git a/cbits/crypton_cpu.c b/cbits/crypton_cpu.c
--- a/cbits/crypton_cpu.c
+++ b/cbits/crypton_cpu.c
@@ -147,6 +147,20 @@
 		leaf1_ecx = ecx;
 		if (!(f & CRYPTON_X86_AVX))
 			leaf1_ecx &= ~(1u << 28);
+		/*
+		 * Bit 11 is not leaf 1's to give.  The assembly reads it as
+		 * AMD's XOP, which lives in leaf 0x80000001, and OpenSSL
+		 * clears whatever leaf 1 put there before merging the real
+		 * flag into the place -- on Intel that is SDBG, the silicon
+		 * debug interface, reported since Broadwell, and reading it
+		 * as XOP sends SHA-512 and ChaCha20 into a vprotq and a
+		 * SIGILL.  It is cleared and left clear: nothing here can run
+		 * XOP to test it, and no processor still in service has it,
+		 * AMD having carried it from Bulldozer to Excavator and Zen
+		 * having dropped it.  That is the reason the AVX-512 bits
+		 * above are cleared too.
+		 */
+		leaf1_ecx &= ~(1u << 11);
 		crypton_ia32cap_P[1] = leaf1_ecx;
 
 		if (maxleaf >= 7) {
diff --git a/crypton.cabal b/crypton.cabal
--- a/crypton.cabal
+++ b/crypton.cabal
@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               crypton
-version:            2.0.0
+version:            2.0.1
 license:            BSD-3-Clause
 license-file:       LICENSE
 copyright:          Vincent Hanquez <vincent@snarc.org>