diff --git a/Library/Homebrew/brew.sh b/Library/Homebrew/brew.sh
index d0b15e080fe30..326a272f83ee0 100644
--- a/Library/Homebrew/brew.sh
+++ b/Library/Homebrew/brew.sh
@@ -23,7 +23,9 @@ if [[ -n "$HOMEBREW_MACOS" ]]
 then
   HOMEBREW_DEFAULT_CACHE="${HOME}/Library/Caches/Homebrew"
   HOMEBREW_DEFAULT_LOGS="${HOME}/Library/Logs/Homebrew"
+  HOMEBREW_DEFAULT_PREFIX="/usr/local"
   HOMEBREW_DEFAULT_TEMP="/private/tmp"
+  HOMEBREW_MACOS_ARM_DEFAULT_PREFIX="/opt/homebrew"
 else
   CACHE_HOME="${XDG_CACHE_HOME:-${HOME}/.cache}"
   HOMEBREW_DEFAULT_CACHE="${CACHE_HOME}/Homebrew"
@@ -429,6 +431,8 @@ export HOMEBREW_MACOS_VERSION_NUMERIC
 export HOMEBREW_USER_AGENT
 export HOMEBREW_USER_AGENT_CURL
 export HOMEBREW_BOTTLE_DEFAULT_DOMAIN
+export HOMEBREW_DEFAULT_PREFIX
+export HOMEBREW_MACOS_ARM_DEFAULT_PREFIX
 
 if [[ -n "$HOMEBREW_MACOS" && -x "/usr/bin/xcode-select" ]]
 then
diff --git a/Library/Homebrew/cmd/update.sh b/Library/Homebrew/cmd/update.sh
index 49baaaa4ede9b..ec1ac12721284 100644
--- a/Library/Homebrew/cmd/update.sh
+++ b/Library/Homebrew/cmd/update.sh
@@ -45,6 +45,18 @@ git_init_if_necessary() {
     trap - EXIT
   fi
 
+  if [[ -n "${HOMEBREW_MACOS_VERSION}" ]] &&
+    [[ -z "$(git config --get homebrew.flavour 2>/dev/null)" ]]
+  then
+    if [[ "${HOMEBREW_PREFIX}" = "${HOMEBREW_MACOS_ARM_DEFAULT_PREFIX}" ]]; then
+      git config --replace-all homebrew.flavour "arm64" 2>/dev/null
+    elif [[ "${HOMEBREW_PREFIX}" = "${HOMEBREW_DEFAULT_PREFIX}" ]]; then
+      git config --replace-all homebrew.flavour "x86_64" 2>/dev/null
+    else
+      git config --replace-all homebrew.flavour "$(uname -m)" 2>/dev/null
+    fi
+  fi
+
   [[ -d "$HOMEBREW_LIBRARY/Taps/homebrew/homebrew-core" ]] || return
   safe_cd "$HOMEBREW_LIBRARY/Taps/homebrew/homebrew-core"
   if [[ ! -d ".git" ]]
diff --git a/Library/Homebrew/install.rb b/Library/Homebrew/install.rb
index 155a4809966cd..14748f5b4de4e 100644
--- a/Library/Homebrew/install.rb
+++ b/Library/Homebrew/install.rb
@@ -14,7 +14,7 @@ module Install
     module_function
 
     def perform_preinstall_checks(all_fatal: false, cc: nil)
-      check_prefix
+      check_flavour_matches_architecture
       check_cpu
       attempt_directory_creation
       check_cc_argv(cc)
@@ -29,19 +29,44 @@ def perform_build_from_source_checks(all_fatal: false)
       Diagnostic.checks(:build_from_source_checks, fatal: all_fatal)
     end
 
-    def check_prefix
-      if Hardware::CPU.intel? && HOMEBREW_PREFIX.to_s == HOMEBREW_MACOS_ARM_DEFAULT_PREFIX
-        odie "Cannot install in Homebrew on Intel processor in ARM default prefix (#{HOMEBREW_PREFIX})!"
-      elsif Hardware::CPU.arm? && HOMEBREW_PREFIX.to_s == HOMEBREW_DEFAULT_PREFIX
-        odie <<~EOS
-          Cannot install in Homebrew on ARM processor in Intel default prefix (#{HOMEBREW_PREFIX})!
-          Please create a new installation in #{HOMEBREW_MACOS_ARM_DEFAULT_PREFIX} using one of the
-          "Alternative Installs" from:
-            #{Formatter.url("https://docs.brew.sh/Installation")}
-          You can migrate your previously installed formula list with:
-            brew bundle dump
+    def check_flavour_matches_architecture
+      homebrew_flavour = HOMEBREW_REPOSITORY.cd do
+        Utils.popen_read("git", "config", "--get", "homebrew.flavour").chomp.presence
+      end
+
+      if !homebrew_flavour ||
+         (Hardware::CPU.intel? && homebrew_flavour == "x86_64") ||
+         (Hardware::CPU.arm? && homebrew_flavour == "arm64")
+        return
+      end
+
+      error_title = "This Homebrew installation in #{HOMEBREW_PREFIX} only works on #{homebrew_flavour} processors."
+      odie error_title unless Hardware::CPU.arm?
+
+      ohai "Checking whether Rosetta is installed"
+      rosetta_installed = quiet_system(
+        "/usr/bin/swift",
+        "#{HOMEBREW_REPOSITORY}/Library/Homebrew/utils/rosetta_installed.swift",
+      )
+      rosetta_instructions = if rosetta_installed
+        <<~EOS
+          To use it, you can:
+          - run your Terminal from Rosetta 2 or
+          - run 'arch -x86_64 brew' instead of 'brew'.
         EOS
+      else
+        "To use it, you need to install Rosetta 2 first."
       end
+
+      odie <<~EOS
+        #{error_title}
+        #{rosetta_instructions}
+        Or create a new installation in #{HOMEBREW_MACOS_ARM_DEFAULT_PREFIX} using one of the
+        "Alternative Installs" from:
+          #{Formatter.url("https://docs.brew.sh/Installation")}
+        You can migrate your previously installed formula list with:
+          brew bundle dump
+      EOS
     end
 
     def check_cpu
diff --git a/Library/Homebrew/utils/rosetta_installed.swift b/Library/Homebrew/utils/rosetta_installed.swift
new file mode 100644
index 0000000000000..480baba90ddb1
--- /dev/null
+++ b/Library/Homebrew/utils/rosetta_installed.swift
@@ -0,0 +1,4 @@
+#!/usr/bin/swift
+
+import CoreFoundation
+exit(CFBundleIsArchitectureLoadable(CPU_TYPE_X86_64) ? 0 : 1)