Simple powershell script to fix arena "Show phases" button bug (see: https://feedback.wizards.com/forums/918667-mtg-arena-bugs-product-suggestions/suggestions/44817385-show-phases-button-in-options-or-pressing-l-don )

ArenaPhaseFixer.ps1

$path = 'HKCU:\SOFTWARE\Wizards Of The Coast\MTGA';
$key = Get-Item $path

$namevalues = $key | Select-Object -ExpandProperty Property | 
ForEach-Object { 
    [PSCustomObject] @{ 
        Name  = $_; 
        Value = $key.GetValue($_) 
    } 
}

$anomalies = $namevalues | 
Where-Object { 
    $_.Name -like '*PhaseLad*' -and $_.Value -gt 1
}

if ($anomalies) {
    $anomalies | ForEach-Object {
        Set-ItemProperty -Path $path -Name $_.Name -Value 1
    }
    
    Write-Host Found and fixed the following values:
    $anomalies | Format-Table
}
else {
    Write-Host No invalid registry values found
}