Adapter.update(dataset) does not alter data base, VB.NET

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VB

OleDb

Using an ms-access-2007 database and trying to edit a certain row/column without success.
I can add new rows to the same data base with code without problems. Trying to reduce my original code to a simplest possible test-code and running it shows no error, but does not alter original data.
The data base has a primary key index (ID). I am writing in VS 2019, vb.net.

What I have tried:

with a msgbox I have checked that ds.Tables(0).Rows(0).Item(4) is altered, but next step with the adapter change the data base fail.
I have also tried with adapter.Update(ds.Table(0)) - same result.

Private Sub Button2_Click_(sender As Object, e As EventArgs) Handles Button2.Click
    'testa att uppdatera databas
    cnnTävl = New OleDb.OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data source=" + TPath + AktTävlNamn + "_" + AktTävlDat + ".mdb")
    Dim strSQL = "Select * FROM Deltagare WHERE Patrull='12' AND Figur='01'"
    Dim cmd As New OleDb.OleDbCommand(strSQL, cnnTävl)
    Dim Adapter As New OleDb.OleDbDataAdapter(cmd)
    Dim ds As New DataSet
    Dim cb As New OleDb.OleDbCommandBuilder(Adapter)
    'Stop
    Try
        cnnTävl.Open()
        Adapter.Fill(ds)
        If ds.Tables(0).Rows.Count = 1 Then
            ds.Tables(0).Rows(0).BeginEdit()
            ds.Tables(0).Rows(0).Item(4) = "Bo Ek"
        Else
            MsgBox("No rows to edit")
            cnnTävl.Close()
            Exit Sub
        End If
        cb.GetUpdateCommand()
        Adapter.Update(ds)
    Catch Er As Exception
        MsgBox("Er= " + Er.Message)
    End Try
    cnnTävl.Close()
End Sub