This script will allow you to update the certificate used in SCOM, using PowerShell.

Update-SCOMCertificate.ps1

param
(
	[string]$FriendlyName,
	[string]$SubjectName,
	[string]$SerialNumber,
	[string]$DateIssued,
	[string]$ExpirationDate,
	[switch]$ShowAllCertificates,
	[switch]$UpdateRegistry
)

# Author: Blake Drumm (blakedrumm@microsoft.com)
# Date Created: June 6th, 2023
# Date Modified: June 14th, 2023

#region ImportCertAndUsePassword

$PathToPassword = 'C:\Certs\password.txt'

#region ExportPassword
if (-NOT $(Get-Item $PathToPassword -ErrorAction SilentlyContinue))
{
	# This Section can be removed once you write the password to a file
	$SecurePassword = ConvertTo-SecureString "Password1" -AsPlainText -Force
	$PasswordBytes = ConvertFrom-SecureString -SecureString $SecurePassword
	Set-Content -Path $PathToPassword -Value $PasswordBytes
	pause
	#endregion
}

$PasswordBytes = Get-Content -Path $PathToPassword
$pwd = ConvertTo-SecureString -String $PasswordBytes

$RDPCertPlusPath = "C:\Certs\$env:COMPUTERNAME-RDPCertPlusPath.pfx"
$RDPCertPlusPathFound = (Resolve-Path -Path $RDPCertPlusPath -ErrorAction SilentlyContinue).Path
if ($RDPCertPlusPath)
{
	$ImportRDPCert = Import-PfxCertificate -FilePath $RDPCertPlusPath -CertStoreLocation Cert:\LocalMachine\My -Password $pwd
	WMIC /namespace:\\root\cimv2\TerminalServicesPATH Win32_TSGeneralSettingSet SSLCertificateSHA1Hash="$($ImportRDPCert.Thumbprint)"
}
else
{
	Write-Host "Cannot find file: $RDPCertPlusPath" -ForegroundColor Red
}

$SCOMPath = "C:\Certs\$env:COMPUTERNAME-SCCM_SCOMCertPlusPath.pfx"
$SCOMPathFound = (Resolve-Path -Path $SCOMPath -ErrorAction SilentlyContinue).Path
if ($SCOMPath)
{
	$ImportSCOMCert = Import-PfxCertificate -FilePath $SCOMPath -CertStoreLocation Cert:\LocalMachine\My -Password $pwd
}
else
{
	Write-Host "Cannot find file: $SCOMPath" -ForegroundColor Red
}



if ($ImportSCOMCert)
{
	$SerialNumber = $ImportSCOMCert.SerialNumber
}
#endregion

# -------------------------------------------------------------------------------------------------
#region Variables
# -------------------------------------------------------------------------------------------------

if (-NOT $FriendlyName)
{
	$FriendlyName = "" # OPTIONAL : This allows you to import a certificate with a specific Friendly Name.
}
if (-NOT $SubjectName)
{
	$SubjectName = "" # OPTIONAL : This allows you to import a certificate with a specific Subject Name. If left blank, the script will check the Subject Name against the computer name of the local machine.
}
if (-NOT $SerialNumber)
{
	$SerialNumber = "" # OPTIONAL : This allows you to import a certificate with a specific Serial Number.
}
if (-NOT $DateIssued)
{
	$DateIssued = "" # OPTIONAL : This allows you to import a certificate with a specific Date Issued. (Example value: 2/7/2023 7:22:52 PM)
}
if (-NOT $ExpirationDate)
{
	$ExpirationDate = "" # OPTIONAL : This allows you to import a certificate with a specific Expiration Date. (Example value: 2/7/2025 7:22:52 PM)
}
if (-NOT $ShowAllCertificates)
{
	[string]$ShowAllCertificates = "No" # OPTIONAL : This allows you to show all the certificates in the Local Computer Personal Certificate Store. (Acceptable values are: (Y)es or (N)o)
}
else
{
	[string]$ShowAllCertificates = "No"
}
if (-NOT $UpdateRegistry)
{
	[string]$UpdateRegistry = "Yes" # REQUIRED : This allows you update the registry with the script, or you can see what happens without the script making changes. (Acceptable values are: (Y)es or (N)o)
}
else
{
	[string]$UpdateRegistry = "Yes"
}


# -------------------------------------------------------------------------------------------------
#endregion
# -------------------------------------------------------------------------------------------------

# DO NOT EDIT PAST THIS LINE

# -------------------------------------------------------------------------------------------------

$RegistryPath = "HKLM:\SOFTWARE\Microsoft\Microsoft Operations Manager\3.0\Machine Settings"

[string]$SerialNumber = $SerialNumber.Replace(" ", "")

$certs = [Array] (Get-ChildItem cert:\LocalMachine\my\) | Sort-Object NotAfter -Descending

foreach ($cert in $certs)
{
	$skipForeach = $null
	# Check if FriendlyName variable is set
	if ($FriendlyName)
	{
		if ($FriendlyName -ne $cert.FriendlyName)
		{
			$skipForeach = $true
		}
	}
	# Check if SubjectName starts with the machine name
	if ($SubjectName)
	{
		if ($cert.SubjectName.Name -notmatch "$SubjectName")
		{
			$skipForeach = $true
		}
	}
	elseif ($cert.SubjectName.Name -notmatch $env:COMPUTERNAME)
	{
		if ($FriendlyName -or $SerialNumber -or $DateIssued -or $ExpirationDate -or ($ShowAllCertificates -match "^(Y|Yes)$"))
		{
			Out-Null
		}
		else
		{
			$skipForeach = $true
		}
	}
	# Check if SerialNumber variable is set
	if ($SerialNumber)
	{
		if ($cert.SerialNumber.ToString().ToLower() -ne "$($SerialNumber.ToLower())")
		{
			$skipForeach = $true
		}
	}
	# Check if Date Issued variable is set
	if ($DateIssued)
	{
		if ($cert.GetEffectiveDateString() -notmatch "$DateIssued")
		{
			$skipForeach = $true
		}
	}
	# Check if ExpirationDate variable is set
	if ($ExpirationDate)
	{
		# Convert from datetime to a string and check if the Expiration Date doesn't equal what is set in the ExprirationDate variable.
		if ($cert.NotAfter.ToString() -notmatch "$ExpirationDate")
		{
			$skipForeach = $true
		}
	}
	elseif ($cert.NotAfter -lt $(Get-Date))
	{
		$skipForeach = $true
	}
	if ($skipForeach)
	{
		continue
	}
	[string]$certSerial = $cert.SerialNumber
	$certSerialReversed = $Null
	$certSerialReversed = [String]("")
	-1 .. -19 | ForEach-Object {
		$certSerialReversed += $($certSerial[2 * $_]) + $($certSerial[2 * $_ + 1])
	}
	Write-Host @"

-----------------------------------------------------------------
"@ -ForegroundColor DarkCyan
	if ($cert.FriendlyName)
	{
		[string]$certFriendlyName = $cert.FriendlyName
	}
	else
	{
		[string]$certFriendlyName = "<null>"
	}
	if ($cert.SubjectName.Name)
	{
		$certSubjectName = $cert.SubjectName.Name
	}
	else
	{
		$certSubjectName = "<null>"
	}
	$certificateIssuedTo = $cert.SubjectName.Name.Split("=").Split(",") | Select-Object -Index 1
	if ($certificateIssuedTo)
	{
		$certIssuedTo = $certificateIssuedTo
	}
	else
	{
		$certIssuedTo = "<null>"
	}
	$fqdn = [System.Net.Dns]::GetHostEntry([System.Net.Dns]::GetHostName()).HostName
	Write-Output @"
Friendly Name:                 $certFriendlyName
Issued To:                     $certIssuedTo
Subject Name:                  $certSubjectName (FQDN of machine: $fqdn)
Date Issued:                   $($cert.NotBefore.ToString())
Expiration:                    $($cert.NotAfter.ToString())
Serial Number:                 $($cert.SerialNumber.ToLower())
Serial Number (Reversed):      $($certSerialReversed.ToLower())
Certificate Hash (Thumbprint): $($cert.Thumbprint.ToLower())
"@
	if ($UpdateRegistry -imatch "^(Y|Yes)$" -and $ShowAllCertificates -notmatch "^(Y|Yes)$")
	{
		Write-Host "Setting registry key values:   $RegistryPath" -ForegroundColor Green
		Set-ItemProperty -Path $RegistryPath -Name ChannelCertificateHash -Value $cert.Thumbprint.ToLower() | Out-Null
		New-ItemProperty -PropertyType Binary -Path $RegistryPath -Name ChannelCertificateSerialNumber -Value ([byte[]](($certSerialReversed -split '([a-fA-F0-9]{2})' | Where-Object { $_ } | ForEach-Object { [byte]("0x$_") }))) -Force | Out-Null
		Write-Host "Restarting Service:            Microsoft Monitoring Agent (HealthService)" -ForegroundColor Green
		Restart-Service HealthService
	}
	if ($ShowAllCertificates -notmatch "^(Y|Yes)$")
	{
		break
	}
}
Write-Host @"
-----------------------------------------------------------------
"@ -ForegroundColor DarkCyan