diff --git a/Config.in.legacy b/Config.in.legacy
index da6f24366c..a746f682cc 100644
--- a/Config.in.legacy
+++ b/Config.in.legacy
@@ -146,6 +146,20 @@ endif
 
 comment "Legacy options removed in 2024.08"
 
+config BR2_x86_knightslanding
+	bool "knightslanding x86 architecture support dropped"
+	select BR2_LEGACY
+	help
+	  GCC 14.x has marked this architecture as obsolete, and emits
+	  a warning causing build failures.
+
+config BR2_x86_knightsmill
+	bool "knightsmill x86 architecture support dropped"
+	select BR2_LEGACY
+	help
+	  GCC 14.x has marked this architecture as obsolete, and emits
+	  a warning causing build failures.
+
 config BR2_PACKAGE_DVB_APPS
 	bool "dvb-apps package removed"
 	select BR2_LEGACY
diff --git a/arch/Config.in.x86 b/arch/Config.in.x86
index 93a223b7ae..f9b32130b2 100644
--- a/arch/Config.in.x86
+++ b/arch/Config.in.x86
@@ -379,30 +379,6 @@ config BR2_x86_grandridge
 	select BR2_X86_CPU_HAS_AVX
 	select BR2_X86_CPU_HAS_AVX2
 	select BR2_ARCH_NEEDS_GCC_AT_LEAST_13
-config BR2_x86_knightslanding
-	bool "knightslanding"
-	select BR2_X86_CPU_HAS_MMX
-	select BR2_X86_CPU_HAS_SSE
-	select BR2_X86_CPU_HAS_SSE2
-	select BR2_X86_CPU_HAS_SSE3
-	select BR2_X86_CPU_HAS_SSSE3
-	select BR2_X86_CPU_HAS_SSE4
-	select BR2_X86_CPU_HAS_SSE42
-	select BR2_X86_CPU_HAS_AVX
-	select BR2_X86_CPU_HAS_AVX2
-	select BR2_ARCH_NEEDS_GCC_AT_LEAST_5
-config BR2_x86_knightsmill
-	bool "knightsmill"
-	select BR2_X86_CPU_HAS_MMX
-	select BR2_X86_CPU_HAS_SSE
-	select BR2_X86_CPU_HAS_SSE2
-	select BR2_X86_CPU_HAS_SSE3
-	select BR2_X86_CPU_HAS_SSSE3
-	select BR2_X86_CPU_HAS_SSE4
-	select BR2_X86_CPU_HAS_SSE42
-	select BR2_X86_CPU_HAS_AVX
-	select BR2_X86_CPU_HAS_AVX2
-	select BR2_ARCH_NEEDS_GCC_AT_LEAST_8
 config BR2_x86_skylake_avx512
 	bool "skylake-avx512"
 	select BR2_X86_CPU_HAS_MMX
@@ -791,8 +767,6 @@ config BR2_GCC_TARGET_ARCH
 	default "tremont"	if BR2_x86_tremont
 	default "sierraforest"	if BR2_x86_sierraforest
 	default "grandridge"	if BR2_x86_grandridge
-	default "knl"		if BR2_x86_knightslanding
-	default "knm"		if BR2_x86_knightsmill
 	default "skylake-avx512" if BR2_x86_skylake_avx512
 	default "cannonlake"	if BR2_x86_cannonlake
 	default "icelake-client" if BR2_x86_icelake_client