Purpose

The purpose of this article is to outline the process to replace an existing Verifone UX410 with a Castles S1U2-M4 on the MM6 and MM6 Mini kiosk. Use the kiosk-specific retrofit kit that matches the exact chassis, processor, and region being serviced.
 

Quick Ordering Process

1. For a UX410 replacement, order the MM6 or MM6 Mini S1U2-M4 retrofit kit for the exact kiosk model in front of you.
2. For a spare or new deployment, order a complete kit rather than a reader-only unit so the adapter plate, harnesses, mounting hardware, and any interface components are included.
3. Verify the work order identifies the correct processor, region, and any optional Ethernet, antenna, or interface-board requirements before dispatch.
    

S1U2-M4 Reader Kit

The standard S1U2-M4 Reader Kit will contain:
 

• S1U2-M4 reader
• MM6-specific (or MM6 Mini-specific) adapter plate or spacer
• MM6-specific (or MM6 Mini-specific) mounting hardware
• Primary power / I-O harness
• Ethernet jumper and or antenna lead if included by the kit
• Any kit-supplied interface board or bracket
   

Process

Clear the following prerequisite list before starting on-site hardware disassembly:

• Verify the kiosk model and confirm the currently installed reader is a Verifone UX410.
   
• Confirm that all retrofit kit components are present and compare the new hardware to the production build before removing anything.
   
• Record the S1U2-M4 serial number or serial numbers before installation.
   
• Photograph the existing cable routing and fastener locations before removal. If working with a support team during this process, sending the support member the pictures is a good backup that they can keep in internal support notes.
   
• Have a credit card or mobile wallet available for final testing.
   
• Do not reuse the UX410 controller with the S1U2-M4.
   

Tools Needed

• Phillips screwdriver
• Small socket or ratchet set (5/16 in / 8 mm commonly used on legacy UX410 hardware)
• 9/32 in socket or nut driver if required by reader standoffs
• Side cutters or flush cutters for zip ties
• Flashlight
• ESD strap
• Test credit card or mobile wallet
   

MM6 Process

Please Note: The MM6 uses a front-opening chassis for service access. Bracket position, spacer thickness, and cable lengths can vary slightly by production run, so compare the retrofit kit against the existing hardware before removing anything.

1. Power down the kiosk and disconnect AC power before opening the chassis. Open the front chassis fully.
   • Support the open front assembly as needed while you work.
      
2. Locate the UX410 reader assembly behind the payment opening and identify the legacy controller or harness associated with the reader.
   • Photograph or label the cable routing before disconnecting anything.
      
3. Disconnect the UX410 power, Ethernet or serial, coax or antenna, and any reader harnesses from the controller and reader.
    
4. Remove the controller or bracket hardware tied to the UX410 and set the legacy controller aside.
    
5. From the rear of the payment opening, remove the nuts and washers securing the UX410.
   • Support the reader from the front so it does not fall.
      
6. Slide the UX410 out through the front and remove any gasket, spacer, or plate that is specific to the legacy reader.
    
7. Compare the new adapter plate or spacer with the payment opening and verify it matches the MM6 retrofit kit before installation.
    
8. Position any supplied gasket or spacer, feed the new harness through the opening, and insert the S1U2-M4 from the front with the screen upright and the contactless target facing the customer.
    
9. Secure the reader from the rear using the kit-supplied hardware. Tighten evenly and do not overtighten the housing.
    
10. Connect the kit-supplied harness to the S1U2-M4 using the port labels on the reader and the harness tags. Connect only the ports called for by the kit or work order.
     
11. If the kit includes Ethernet or an antenna lead, connect them now and dress the cables so they clear hinges, latches, and the closing path of the front chassis.
     
12. Mount any included interface board or bracket in the approved service location.
    • Do not reinstall the UX410 controller.
       
13. Re-tie the cable bundle, leaving enough slack for future service access.
     
14. Next, test the reader to confirm payment function.
     
15. Restore power to the kiosk and allow both the kiosk and reader to boot fully.
     
16. Confirm the reader display powers on and that the device is detected in the kiosk or service menu.
     
17. Run a test transaction using a supported payment method such as tap, chip, or swipe as applicable.
     
18. Verify the transaction reaches the host and that the kiosk returns to the ready screen.
     
19. Close and lock the kiosk once testing is complete.
     

MM6 Mini Process

The MM6 Mini field flow mirrors the published UX410 Help Desk article, Verifone - UX410 Installation Guide for Gen3 and MM6 Mini
 

1. Unlock the kiosk and open the front door fully.
   
    
2. Locate the legacy UX410 controller on the inside wall of the kiosk.
   
    
3. Disconnect cabling from the legacy controller and reader. Remove the power lead first, then Ethernet or COM, then any coax or antenna connection.
    
4. Remove the controller mounting hardware and pull the controller away from the kiosk.
   
    
5. From the rear of the payment opening, remove the nuts and washers that secure the UX410. Support the reader from the front while it is freed.
    
6. Slide the UX410 out through the front and remove any gasket, spacer, or mounting plate left in the opening.
    
7. Compare the new MM6 Mini adapter plate or spacer with the payment opening and confirm the orientation before installation.
    
8. Feed the new harness through the opening and insert the S1U2-M4 from the front with the screen upright and the contactless target facing the customer.
   
9. Secure the reader from the rear using the kit hardware. Tighten evenly and do not twist the housing.
    
10. Mount the new controller or interface bracket using the approved holes or the bracket supplied in the kit.
     
11. Connect power to the keyed power connector on the reader harness or controller assembly.
     
12. Connect Ethernet to LAN and connect COM or USB only if specifically called for by the supplied harness labels or work order.
     
13. Route cables away from the hinge and door path, re-tie the bundle, verify service slack, and close the kiosk.
     
14. Restore power to the kiosk and allow the reader to complete its startup sequence.
     
15. Confirm the reader powers on and is recognized by the kiosk.
     
16. Run at least one supported test transaction.
     
17. Verify the kiosk returns to the ready screen with no reader errors.
     
18. Close and lock the kiosk once the test is successful.
     

S1U2-M4 Port Reference

The S1U2-M4 includes several labeled ports and controls on the rear and side of the terminal. Not every port is used on every 365 retrofit kit, so follow the kit labels and work order first. 

If a kit packing slip, regional work order, or support instruction conflicts with this guide, follow the kit-specific document for the build you are servicing.