Checkbox column default value in data grid view

I have a csv spec file I read into a List of strings. Then add it to a datagridview and add a checkbox column. I want to check all of the checkboxes, but nothing has worked. Tried looping through each row and setting the value to true, also tried to set the default values needed row event but no luck. Any ideas?

DataTable dtSpecs = new DataTable();

string[] tmpHeaders = specList[0].Split(','); 

foreach (var header in tmpHeaders)
{
    dtSpecs.Columns.Add(header, typeof(string));
}

for (int i = 1; i < specList.Count; i++)
{
    dtSpecs.Rows.Add(specList[i].Split(','));
}

dataGridView2.DataSource = dtSpecs;

DataGridViewCheckBoxColumn ckb2 = new DataGridViewCheckBoxColumn();
ckb2.HeaderText = "Enable";
ckb2.ValueType = typeof(bool);
dataGridView2.Columns.Insert(0, ckb2);

//This didn't work
for (int i = 0; i < dataGridView2.Rows.Count; i++)
{
    dataGridView2.Rows[i].Cells[0].Value = true;
}

//This way also didn't work
foreach (DataGridViewRow row in dataGridView2.Rows)
{
    row.Cells[0].Value = true;
}

//Also tried this but still nothing checked
private void dataGridView2_DefaultValuesNeeded(object sender, DataGridViewRowEventArgs e)
{
    e.Row.Cells[0].Value = true;
}