Fixing an EZ-FLASH Jr that Fails To Boot
Channel: makho
Date: 2021-01-19

If you have an EZ-FLASH Jr that gets stuck booting, the solution I employed in this video may also work for you. Before even disassembling your cart though, you should verify with the seller the status of any warranty especially since this issue seems to manifest immediately and not after a few months or so. Official resellers will offer a warranty, unofficial resellers probably don't (but check anyway).

This will NOT fix any carts that no longer boot due to a failed firmware update. You'll have to reflash the FPGA over the JTAG header if you can extract the verilog from the *.GB update file. 

Now that that is out of the way, the problem appears to be created during the initial assembly of these carts. The specific cause is unknown to me but the symptom presents as a cart that will no longer work properly due to a failed solder joint. Due to the thin PCB and the mechanical interface, the process of inserting and removing these carts from a GB will cause the board to flex and any poorly done solder joints can fail after just a few cycles. 

This same problem DOES affect OEM carts (though the time scale is much different since those had much better QA) and the solution is pretty much the same. You need to redo any bad joints and repair any damage that was caused by the joints failing (re-align pins, etc). 

Oh, and before anyone complains, yes, these carts ARE tested from the factory. In order to program the XILINX Spartan FPGA these carts use, the carts must be assembled first. So if the FPGA is unable to be programmed, the cart was not assembled properly. 

In the end, I'm unsure which specific chip had the problem because it was quicker to do every joint at the same time and then try it rather than do one chip, clean, try, next chip, clean, try, rinse repeat. Due to the manufacturing issues the Everdrive GBA-X5 Mini had, I assumed the BGA chips were at fault on this cart too but after noticing the bent pins on the XILINX chip after hitting it with hot air, I think that chip may have actually been the culprit. Take a look at this imgur album for some pics of the XILINX chip while I was working on it: https://imgur.com/a/Gjx2KVq

Anyway, in the end, it is still absolutely worth just doing a warranty return rather than DIY. This is NOT an easy solder job. Even if you can DIY this sort of thing, it's still best to return it as return cases will make the manufacturer aware of assembly issues with their product. I don't know how wide-spread this issue is but based on the other threads on gbatemp, I know that other people HAVE run into this issue. 

https://gbatemp.net/threads/ez-flash-junior-faulty.580141/#post-9327880

https://gbatemp.net/threads/ez-flash-junior-wont-boot-nintendo-logo-is-glitched.578431/#post-9327637

Want an EZ-FLASH Jr for yourself? RGRS is an official reseller: https://retrogamerepairshop.com/products/ez-flash-junior

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