diff --git a/Library/Homebrew/extend/ENV/shared.rb b/Library/Homebrew/extend/ENV/shared.rb
index e4a15d299392c37c3e55f945cca0faf46eff0a2c..36b84cf50bcd3ac72e8247a01d900de7029a3e70 100644
--- a/Library/Homebrew/extend/ENV/shared.rb
+++ b/Library/Homebrew/extend/ENV/shared.rb
@@ -255,7 +255,7 @@ module SharedEnvExtension
   # @private
   def effective_arch
     if Homebrew.args.build_bottle? && Homebrew.args.bottle_arch
-      Homebrew.args.bottle_arch
+      Homebrew.args.bottle_arch.to_sym
     else
       Hardware.oldest_cpu
     end
diff --git a/Library/Homebrew/extend/os/linux/extend/ENV/shared.rb b/Library/Homebrew/extend/os/linux/extend/ENV/shared.rb
index 0ebba4f6bc7efd6c081772cd8f620d96d1db19db..a7eb3b9671e2180e3d1324aa5227e3926cbdbf17 100644
--- a/Library/Homebrew/extend/os/linux/extend/ENV/shared.rb
+++ b/Library/Homebrew/extend/os/linux/extend/ENV/shared.rb
@@ -3,8 +3,10 @@
 module SharedEnvExtension
   # @private
   def effective_arch
-    if Homebrew.args.build_bottle?
-      Homebrew.args.bottle_arch || Hardware.oldest_cpu
+    if Homebrew.args.build_bottle? && Homebrew.args.bottle_arch
+      Homebrew.args.bottle_arch.to_sym
+    elsif Homebrew.args.build_bottle?
+      Hardware.oldest_cpu
     else
       :native
     end
diff --git a/Library/Homebrew/formula_installer.rb b/Library/Homebrew/formula_installer.rb
index 18ed7cb437d28e9b76573dc6b4f191ed9d465238..c2f07c73e204bedd9d4931a9e3f1015f44c9baa5 100644
--- a/Library/Homebrew/formula_installer.rb
+++ b/Library/Homebrew/formula_installer.rb
@@ -269,7 +269,7 @@ class FormulaInstaller
 
     return if only_deps?
 
-    if build_bottle? && (arch = Homebrew.args.bottle_arch) && !Hardware::CPU.optimization_flags.include?(arch)
+    if build_bottle? && (arch = Homebrew.args.bottle_arch) && !Hardware::CPU.optimization_flags.include?(arch.to_sym)
       raise "Unrecognized architecture for --bottle-arch: #{arch}"
     end