$f = 'C:/Users/77338/Desktop/STM32-OTA/STM32F103_App1/Src/main.c'
$bytes = [System.IO.File]::ReadAllBytes($f)

# Count literal \r\n sequences (0x5C 0x72 0x5C 0x6E)
$pat = @(0x5C, 0x72, 0x5C, 0x6E)
$count = 0
$out = [byte[]]::new($bytes.Count)
$j = 0
$i = 0
while ($i -lt $bytes.Count) {
    $match = $true
    for ($k = 0; $k -lt 4; $k++) {
        if ($i + $k -ge $bytes.Count -or $bytes[$i + $k] -ne $pat[$k]) { $match = $false; break }
    }
    if ($match) {
        $i += 4
    } else {
        $out[$j++] = $bytes[$i++]
    }
}
[Array]::Resize([ref]$out, $j)
[System.IO.File]::WriteAllBytes($f, $out)
Write-Host "Removed $count \r\n sequences, $j bytes written"