I am creating a migration bundle for external usage by our database team to execute Entity Framework Migrations. The bundle is composed of an Entity Framework Project (which includes all our migrations) and the `ef6.dll` migration tool from the Entity Framework 6.4 NuGet package, which is located at `ef64package/tools/netcoreapp3.0/any`.

The migration bundle also contains a simple PowerShell script that executes `ef6.dll` somehow like this:

```
dotnet .\ef6.dll database update --verbose --assembly MyApp.Core.EF.dll --connection-string "Data Source=localhost;Initial Catalog=MyApp;Trusted_Connection=True;" --connection-provider "System.Data.SqlClient"

```

Using the `migrate.exe` (in previous versions of Entity Framework) and `ef6.exe` for .NET Framework this bundle worked just fine. But after switching to .NET Core and `ef6.dll` the execution results in the following error:

```
Specify the '-Verbose' flag to view the SQL statements being applied to the target database.
System.NullReferenceException: Object reference not set to an instance of an object.
   at System.Data.Entity.Internal.LazyInternalConnection.CreateConnectionFromProviderName(String providerInvariantName)
   at System.Data.Entity.Internal.LazyInternalConnection.InitializeFromConnectionStringSetting(ConnectionStringSettings appConfigConnection)
   at System.Data.Entity.Internal.LazyInternalConnection.Initialize()
   at System.Data.Entity.Internal.LazyInternalConnection.get_Connection()
   at System.Data.Entity.Internal.LazyInternalContext.get_Connection()
   at System.Data.Entity.Infrastructure.DbContextInfo..ctor(Type contextType, DbProviderInfo modelProviderInfo, AppConfig config, DbConnectionInfo connectionInfo, Func`1 resolver)
   at System.Data.Entity.Infrastructure.DbContextInfo..ctor(Type contextType, DbConnectionInfo connectionInfo)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration, DbContext usersContext, DatabaseExistenceState existenceState, Boolean calledByCreateDatabase)
   at System.Data.Entity.Migrations.DbMigrator..ctor(DbMigrationsConfiguration configuration)
   at System.Data.Entity.Infrastructure.Design.Executor.CreateMigrator(DbMigrationsConfiguration configuration)
   at System.Data.Entity.Infrastructure.Design.Executor.UpdateInternal(String targetMigration, Boolean force, DbConnectionInfo connectionInfo, String migrationsConfigurationName)
   at System.Data.Entity.Infrastructure.Design.Executor.Update.<>c__DisplayClass0_0.<.ctor>b__0()
   at System.Data.Entity.Infrastructure.Design.Executor.OperationBase.Execute(Action action)
Object reference not set to an instance of an object.

```

A very generic error, but according to the EF source code (<https://github.com/dotnet/ef6/blob/02104044fae2aca5d3a1f50f55f4af940a3c64a8/src/EntityFramework/Internal/LazyInternalConnection.cs>), i looks like a `DbProviderFactory` registration is missing or the `providerInvariantName` is messed up in the process. I've got a feeling this is a side effect due to a missing configuration or dependency. But so far i could not figure out how to fix this error.

Any ideas on how to fix this error?
Also other approaches in creating a standalone migration bundle are highly welcome.

Thanks in advance!