Hi, I would like to share our development which will meet the above requirement. Please refer the below link and it will be helpful to make partial payment in POS and backend. https://www.odoo.com/apps/modules/11.0/skit_pay_later/

youtube link: https://www.youtube.com/watch?v=hq1XXXfcJFQ

create a product (service type) and call it "advance payment from customer); available for the POS.

Create a specific payment method for the POS and a specific accounting journal to record these payments (debit bank account and credit customer account ).

At the time of payment a cash ticket will be printed.

when the customer confirm his order for product XYZ you will be able to deduct the payment in advance (adding the prepayment with a Minus sign on quantity for the amount already received in advance); it should make the trick; waiting for a proper and more integrated solution from Odoo. (at the time I am wrinting this may have been done for V10)

I'm also looking for some code/module that can handle this (using Odoo 11).

Hello, also looking for a reply to the same question. ..