Xiaomi R4C USB MOD

Hardware Questions and Recommendations
1

Pardon me, the guides on the openwrt forum how to mod the usb aren't detailed. Can i have the detailed guide in modding the usb.

2

See https://openwrt.org/toh/xiaomi/xiaomi_mi_router_4c#hardware_mod_-_usb_port

If anything is unclear, please state exactly where you have problems.

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3

Soldering the pin marking, do i just solder the usb socket directly or i need a cable to make the line in order. And the heatsink in the processor, how do i put it out from the processor?

4

did you see this:

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5

Hello, here is link for moding Mi 4A, tehnique is same just pinout on board is different. Use pins on board from Mi 4C but u can make rest same.

@RadioOperator when will be page for Mi4A 100m edition be updated with this hardware mod?
RadioOperator

6

Sorry, I do not know.

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7

Hey, how to i remove the heatsink, do i need a heater gun?. And can you explain more the connection from D+ and D-, data 5V and ground connection to usb?

8

Heatsink is usualy fixed on with thermal pad/sticker. I usualy take long nose (needle nose) pliers and gently twist it while pooling out (more twisting than pooling, and care to not scratch board or pins) then it will come loose without damaging the thermal pad and heatsink that you reuse later. About usb soldier with wire to its position on usb female connection. https://components101.com/sites/default/files/component_pin/USB-A-Jack-Pinout.png
Add 15k resistor from d+ to gnd and 15k resistor from d- to gnd.

9

Since it's a wiki, you can do it yourself, you don't have to wait for someone doing it.
See Applying for OpenWrt wiki account for getting a wiki account.

10

So Ground -> 15k ohm resistor -> D+ and D-
from 15k ohm resistor -> wire Usb female socket

or Ground -> 15k ohm resistor -> D+ and D- -> wire usb female socket

11

And just pull with twisting the thermal pad or pull with circling the thermal pad?, then how do i put the thermal pad back? With glue?

12

If you do slow and properly, termal pad will stay whole and u can use it again when return heatsink to MCU. And for 15k res to ground do it as on picture.

U dont need 15k res to 3.3v. i think i read somewhere that one res is tied on internaly or via some other pad. U can check datasheet if you are intrested further more.

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13

So i can use same ground to usb female too?, and for placing the thermal pad again, do i just need to put it down or need some glue?

14

What's the symbol meaning in middle of the connection ?

15

Yes same ground. That is continuity of connection representation

16

for the thermal pad, do i just put in again in the processor or else

17

Hey, pardon me you have the firmware that have the usb ehci turned on

18

Yes just slap it back on same position with heatsink.
And about firmware no srry i dont have i swiched to new project.

19

Ask @Rubrex i compiled firmware for him while i had setup for Mi 4C

20

Thanks, and can i use a pinset to remove the heatsink and thermalpad?