By default CRM will not allow you save the data assigned to
readonly field. For that we have use below javascript code snippet to make this
work.
For ex new_amount is the readonly field in your form. So to save
the data assigned to it use the below code snippet
function
SetSubmitForAmountField()
{
Xrm.Page.getAttribute("new_amount").setSubmitMode("always");
}
You have to call this function on onsave of your form as shown below.