The ONT at a customer location has nothing to do with DHCP or PPPoE. It is the gateway router on Verizon's end that hands out internet connections either DHCP or PPPoE.
You cannot make your connection work with DHCP just by changing your router's settings. Also, upgrading your router's firmware will not help. Verizon would need to update equipment on its end to allow DHCP.
The Actiontec MI424WR router supplied by Verizon will automatically detect whether the gateway is using PPPoE or DHCP and will select to correct protocol to make the connection.
You can determine if you are DHCP or PPPoE from your router's main status page.
If the main status page shows Connected Broadband coax or broadband ethernet, your connection is DHCP.
If the main status page shows Connected WAN PPPoE or WAN PPPoE 2, your connection is PPPoE.