diff --git a/Microsoft.PowerShell_profile.ps1 b/Microsoft.PowerShell_profile.ps1
index 3c63221..26fceb6 100644
--- a/Microsoft.PowerShell_profile.ps1
+++ b/Microsoft.PowerShell_profile.ps1
@@ -900,6 +900,18 @@ function Update-Profile {
                 foreach ($dir in $profileDirs) {
                     $target = Join-Path $dir "Microsoft.PowerShell_profile.ps1"
                     if (Test-Path $dir) {
+                        # Back up the current profile before overwriting it, keeping the latest five
+                        # (profile.original.ps1 is never matched, so the first-install copy survives).
+                        if (Test-Path -Path $target -PathType Leaf) {
+                            try {
+                                $backupStamp = Get-Date -Format 'yyyyMMdd-HHmmss'
+                                Copy-Item -Path $target -Destination (Join-Path $dir "oldprofile.$backupStamp.ps1") -Force -ErrorAction Stop
+                                Get-ChildItem -Path $dir -Filter 'oldprofile*.ps1' -ErrorAction SilentlyContinue |
+                                    Sort-Object LastWriteTime -Descending | Select-Object -Skip 5 |
+                                    ForEach-Object { Remove-Item $_.FullName -Force -ErrorAction SilentlyContinue }
+                            }
+                            catch { Write-Warning "Could not back up $target before update: $_" }
+                        }
                         try {
                             Copy-Item -Path $tempProfile -Destination $target -Force -ErrorAction Stop
                             $copySuccess++
@@ -1991,10 +2003,14 @@ function sed($file, $find, $replace) {
     }
     if ($null -eq $find -or $find -eq '') { Write-Error "Usage: sed <file> <find> <replace>"; return }
     if ($null -eq $replace) { $replace = '' }
-    $content = Get-Content -LiteralPath $file -Raw
+    $resolved = (Resolve-Path -LiteralPath $file).Path
+    # Read as UTF-8 (BOM-aware) so non-ASCII content survives the rewrite on Windows PowerShell 5.1.
+    $content = Get-Utf8FileText $resolved
     if ($null -eq $content -or $content.Length -eq 0) { Write-Warning "File is empty: $file"; return }
     $utf8NoBom = [System.Text.UTF8Encoding]::new($false)
-    [System.IO.File]::WriteAllText((Resolve-Path -LiteralPath $file).Path, $content.replace("$find", $replace), $utf8NoBom)
+    # Keep a single .bak of the pre-edit content, like sed -i.bak.
+    Copy-Item -LiteralPath $resolved -Destination "$resolved.bak" -Force -ErrorAction SilentlyContinue
+    [System.IO.File]::WriteAllText($resolved, $content.replace("$find", $replace), $utf8NoBom)
 }
 
 # Show the full path of a command
@@ -3575,7 +3591,16 @@ function Uninstall-Profile {
     )
     foreach ($dir in $profileDirs) {
         $mainProfile = Join-Path $dir 'Microsoft.PowerShell_profile.ps1'
-        if (Test-Path $mainProfile) {
+        $originalBackup = Join-Path $dir 'profile.original.ps1'
+        if (Test-Path $originalBackup) {
+            # Restore the pre-install profile saved on first install instead of leaving none behind.
+            if ($PSCmdlet.ShouldProcess($mainProfile, 'Restore original profile saved before first install')) {
+                Copy-Item -Path $originalBackup -Destination $mainProfile -Force -ErrorAction SilentlyContinue
+                Remove-Item $originalBackup -Force -ErrorAction SilentlyContinue
+                Write-Host "  Restored original profile to $mainProfile" -ForegroundColor Green
+            }
+        }
+        elseif (Test-Path $mainProfile) {
             if ($PSCmdlet.ShouldProcess($mainProfile, 'Remove profile file')) {
                 Remove-Item $mainProfile -Force -ErrorAction SilentlyContinue
                 Write-Host "  Removed $mainProfile" -ForegroundColor DarkGray
diff --git a/README.md b/README.md
index 4d263ab..1bf3b6a 100644
--- a/README.md
+++ b/README.md
@@ -49,8 +49,15 @@ The **install wizard runs by default** — pick theme / scheme / font / features
 Inspired by [powerlevel10k](https://github.com/romkatv/powerlevel10k)'s `p10k configure`. **Runs automatically on every interactive install** — it's the default experience, not an opt-in. Non-interactive environments skip it.
 
 ```powershell
-# Default trusted-download flow — wizard runs as part of installation
+# Recommended (review first): run with no hash flag. setup.ps1 downloads the bundle,
+# prints its SHA-256 hashes, and stops WITHOUT installing. Review them (ideally against
+# the commit list at https://github.com/26zl/PowerShellPerfect/commits/main), then re-run
+# pinning the combined hash for a verified install (the wizard runs during install):
 $setup = irm "https://github.com/26zl/PowerShellPerfect/raw/main/setup.ps1"
+& ([scriptblock]::Create($setup))                                    # prints hashes, then stops
+& ([scriptblock]::Create($setup)) -ExpectedSha256 '<combined-hash>'  # verified install
+
+# Unverified fallback: skip the integrity check and install whatever was just downloaded.
 & ([scriptblock]::Create($setup)) -SkipHashCheck
 
 # Bypass the wizard and apply repo defaults (Tokyo Night + CascadiaCode):
@@ -63,6 +70,8 @@ $setup = irm "https://github.com/26zl/PowerShellPerfect/raw/main/setup.ps1"
 Reconfigure-Profile
 ```
 
+> Same guarantee as the Quick Install above: the printed hash proves download integrity, not upstream authenticity (see the note there). A signed-release or tag-pinning model would add authenticity and is left as a maintainer follow-up.
+
 **Steps** (all accept Enter to keep the default / skip):
 
 1. **Quick start** — one-key preset: Tokyo Night scheme, CascadiaCode Nerd Font, VS Code editor, dark chrome, default features. Answer yes to jump straight to the summary.
diff --git a/setup.ps1 b/setup.ps1
index 30ee655..0e4b804 100644
--- a/setup.ps1
+++ b/setup.ps1
@@ -299,7 +299,7 @@ function Save-WizardChoices {
     )
     $utf8 = [System.Text.UTF8Encoding]::new($false)
     $s = if (Test-Path $UserSettingsPath) {
-        try { (Get-Content $UserSettingsPath -Raw | ConvertFrom-Json -ErrorAction Stop) }
+        try { (Get-Content $UserSettingsPath -Raw -Encoding UTF8 | ConvertFrom-Json -ErrorAction Stop) }
         catch { [PSCustomObject]@{} }
     }
     else { [PSCustomObject]@{} }
@@ -426,7 +426,7 @@ function Start-InstallWizard {
     # Resume from state file if caller passed one that exists
     if ($StatePath -and (Test-Path $StatePath)) {
         try {
-            $prev = Get-Content $StatePath -Raw | ConvertFrom-Json
+            $prev = Get-Content $StatePath -Raw -Encoding UTF8 | ConvertFrom-Json
             $prevSchema = if ($prev.PSObject.Properties['schemaVersion']) { [int]$prev.schemaVersion } else { 1 }
             if ($prevSchema -ne $WIZARD_STATE_SCHEMA) {
                 Write-Host ''
@@ -1107,7 +1107,7 @@ if ($wantWizard) {
 try {
     $configTmp = Join-Path $env:TEMP ("psp-theme-" + [System.IO.Path]::GetRandomFileName() + ".json")
     Copy-Item (Resolve-SetupSourcePath -Kind 'theme') $configTmp -Force -ErrorAction Stop
-    $profileConfig = Get-Content $configTmp -Raw | ConvertFrom-Json
+    $profileConfig = Get-Content $configTmp -Raw -Encoding UTF8 | ConvertFrom-Json
     Copy-Item $configTmp (Join-Path $configCachePath "theme.json") -Force
     Remove-Item $configTmp -ErrorAction SilentlyContinue
 }
@@ -1120,7 +1120,7 @@ $terminalConfig = $null
 try {
     $terminalConfigTmp = Join-Path $env:TEMP ("psp-terminal-" + [System.IO.Path]::GetRandomFileName() + ".json")
     Copy-Item (Resolve-SetupSourcePath -Kind 'terminal') $terminalConfigTmp -Force -ErrorAction Stop
-    $terminalConfig = Get-Content $terminalConfigTmp -Raw | ConvertFrom-Json
+    $terminalConfig = Get-Content $terminalConfigTmp -Raw -Encoding UTF8 | ConvertFrom-Json
     Copy-Item $terminalConfigTmp (Join-Path $configCachePath "terminal-config.json") -Force
     Remove-Item $terminalConfigTmp -ErrorAction SilentlyContinue
 }
@@ -1153,7 +1153,7 @@ $script:WtManaged = $true
 $userSettingsPath = Join-Path $configCachePath "user-settings.json"
 if (Test-Path $userSettingsPath) {
     try {
-        $userSettings = Get-Content $userSettingsPath -Raw | ConvertFrom-Json
+        $userSettings = Get-Content $userSettingsPath -Raw -Encoding UTF8 | ConvertFrom-Json
         # windowsTerminal.manage = false hands settings.json to another tool, such as a dotfiles repo.
         if ($userSettings.windowsTerminal -and $userSettings.windowsTerminal.PSObject.Properties['manage'] -and $userSettings.windowsTerminal.manage -eq $false) { $script:WtManaged = $false }
         if ($profileConfig -and $userSettings.theme) {
@@ -1217,6 +1217,13 @@ foreach ($dir in $profileDirs) {
         $tempDownload = Join-Path $env:TEMP ("psp-profile_download_" + (Split-Path $dir -Leaf) + "_" + [System.IO.Path]::GetRandomFileName() + ".ps1")
         Copy-Item (Resolve-SetupSourcePath -Kind 'profile') $tempDownload -Force -ErrorAction Stop
         if (Test-Path -Path $targetProfile -PathType Leaf) {
+            # Preserve the pre-install profile once as an immutable copy that rotation never deletes
+            # and Uninstall-Profile restores; oldprofile* rotation below never matches this name.
+            $originalBackup = Join-Path $dir 'profile.original.ps1'
+            if (-not (Test-Path -Path $originalBackup)) {
+                Copy-Item -Path $targetProfile -Destination $originalBackup -Force
+                Write-Host "  Original profile saved to [$originalBackup]" -ForegroundColor DarkGray
+            }
             # Keep the latest five timestamped profile backups.
             $backupStamp = Get-Date -Format 'yyyyMMdd-HHmmss'
             $backupPath = Join-Path $dir ("oldprofile.$backupStamp.ps1")
@@ -1402,13 +1409,13 @@ function Install-OhMyPoshTheme {
         $alreadyValid = $false
         if (Test-Path -LiteralPath $themeFilePath -PathType Leaf) {
             try {
-                $null = Get-Content $themeFilePath -Raw -ErrorAction Stop | ConvertFrom-Json
+                $null = Get-Content $themeFilePath -Raw -Encoding UTF8 -ErrorAction Stop | ConvertFrom-Json
                 $alreadyValid = $true
             } catch { $null = $_ }
         }
         if (-not $alreadyValid) {
             Invoke-DownloadWithRetry -Uri $ThemeUrl -OutFile $themeFilePath
-            $null = Get-Content $themeFilePath -Raw | ConvertFrom-Json
+            $null = Get-Content $themeFilePath -Raw -Encoding UTF8 | ConvertFrom-Json
             Write-Host "  Theme '$ThemeName' downloaded." -ForegroundColor Green
         }
         else {
@@ -1606,7 +1613,7 @@ foreach ($wtSettingsPath in $wtSettingsPaths) {
         $wt = $null
         for ($wtAttempt = 1; $wtAttempt -le 2; $wtAttempt++) {
             try {
-                $wtRaw = (Get-Content $wtSettingsPath -Raw) -replace $jsoncCommentPattern, ''
+                $wtRaw = (Get-Content $wtSettingsPath -Raw -Encoding UTF8) -replace $jsoncCommentPattern, ''
                 $wt = $wtRaw | ConvertFrom-Json
                 break
             }