Hacking EZ-Flash Junior - faulty?

[ez80a]

Hello,

I've received my cart before new year's eve and since that I couldn't get it to work.

Hardware: Unmodded Gameboy Color CGB-001; Board CGB-CPU-05; CPU with "D" letter
SD cards: new and used Sandisk Extreme 32GB, Sandisk Ultra 16GB (Red and White), Toshiba 8GB, Goodram 16GB and some others.

At first, console was stuck on loading screen and nothing else happenes.

I've cleaned slot in console, and sd card in cartridge, no luck.
I've disassembled cart to see, if anything is wrong with it and found suspicious solder joints on fpga, so I fixed them with an soldering iron. Now, cart is stuck on osinit message, ocassionally screen goes blank after osinit or shows garbage for 1s and then goes blank again. Okay, some progress...

I've tested kernel 3, 4 and 5 and so far, only on kernel 3 cart booted once to menu, then... guess what? Crash.
Before it I saw, that cartridge has FW4.

uSD cards were treated with h2wtest, then zeroed with dmde tool and formatted as FAT32, 32k cluster. Only ezgb.dat and update_fw files were on cards.

Being a bit curious, I've disassembled gameboy and checked power rails with an oscilloscope and multimeter - 5V rail around 4,965V on cartridge slot.
Battery inside cart is good (2,976V)

System was powered from fresh Duracell, Energizer, Panasonic AA batteries and bench power supply with voltage set max to 3,7V, but it doesn't make any difference.

And the last one: Console works fine with other cartridges I own.

Is there any clue what might be problem?
I don't have any other console than this, but probably I will buy older DMG-01 to see, if this one doesn't like this cartridge.

Greetings.

 

[EZ-Flash2]

What is the current situation, please?
What state is the boot up stuck in?
LOADING?
OSINIT?

 

[ez80a]

What is the current situation, please?
What state is the boot up stuck in?
LOADING?
OSINIT?

Hi,

Depends on kernel, which I put onto uSD card.

Kernel 3.0:
Hangs after OSINIT with blank screen, but before I see garbage on screen for about one second.

Kernel 4.0 and 5.0:
Hangs on OSINIT, it rarely goes further, but with blank screen

 

[EZ-Flash2]

Hi,

Depends on kernel, which I put onto uSD card.

Kernel 3.0:
Hangs after OSINIT with blank screen, but before I see garbage on screen for about one second.

Kernel 4.0 and 5.0:
Hangs on OSINIT, it rarely goes further, but with blank screen

This situation usually occurs when the SD card is not formatted properly or too slow, but as you said in your post above, you replaced multiple SD cards included our recommended SANDISK 32GB red. and also formatted to FAT32+32KB as we told.

So I'm confused too.

 

[Allora]

Another factor in this that i discovered is that low batteries in the system, while they may work in regular carts, if your batteries are low enough, this constant reboot/getting stuck booting, etc problem seems to happen pretty consistently.

In my Gameboy Pocket, after replacing the batteries with a new set, all of these problems disappeared.

 

[ez80a]

Another factor in this that i discovered is that low batteries in the system, while they may work in regular carts, if your batteries are low enough, this constant reboot/getting stuck booting, etc problem seems to happen pretty consistently.

In my Gameboy Pocket, after replacing the batteries with a new set, all of these problems disappeared.

In my opinion, good batteries and good power supply (not that original power brick from nintendo) should be able to handle this cartridge.

This situation usually occurs when the SD card is not formatted properly or too slow, but as you said in your post above, you replaced multiple SD cards included our recommended SANDISK 32GB red. and also formatted to FAT32+32KB as we told.

So I'm confused too.

To be honest, I was very disappointed, but finally I managed to get it to work on my gameboy
All I had to do was to re-solder whole cartridge. BGA chips were horrible to do without solder balls

 

[EZ-Flash2]

In my opinion, good batteries and good power supply (not that original power brick from nintendo) should be able to handle this cartridge.



To be honest, I was very disappointed, but finally I managed to get it to work on my gameboy
All I had to do was to re-solder whole cartridge. BGA chips were horrible to do without solder balls

This is the most massive repair by yourself project I've ever seen.