Gekkio's Technical Blog

Game Boy Advance boards have a 10 nF capacitor C62 between the d-pad up input and ground, but other d-pad buttons have no capacitor.

Thanks to the "great" effort of Elon Musk, Twitter is in flames and I've suddenly realized all my data there is potentially at risk.

Flash cartridges (= "carts") are commonly used to run Game Boy ROMs, such as homebrew games or dumped officially released games, on real hardware.

Biverting a greyscale Game Boy screen is a very popular mod, because it's widely considered to increase the screen contrast.

This time I've decapped an STMicro L78M05CV, a fixed 5.0V linear regulator chip.

This time I've decapped a Microchip PIC16LC72A, an 8-bit PIC microcontroller chip.

This time I've decapped a Texas Instruments OPA1632, a fully-differential operational amplifier chip.

I've decided to start decapping random chips I've harvested from various boards to practice both the decapping procedure and imaging/stitching of microscope photos.

This time I wanted to post some photos of old PCBs I've designed in the last couple of years.

I gave a presentation about Game Boy reverse engineering at Disobey 2018, a security/hacking-oriented conference held in Helsinki.

I own an SFC (Super Famicom, "Japanese SNES") that I use for running hardware tests on Super Game Boy and Super Game Boy 2 systems.

I've made some progress in my research, but don't have any mindblowing findings to share yet.

Game Boy test ROMs are crucial tools for verifying the collective understanding of the Game Boy hardware.

It's been a while since the last time I wrote anything about Game Boys.

Last year I took PCB photos of all Game Boy games I own, but I never managed to categorize or publish the photos I'm not going to analyze all of these in detail, so I'm just going to leave the photos and basic information here for those who are interested…

I've decided that it's time to do a proper release of Mooneye GB after more than one year of development.

I'm happy to announce that I've succeeded in dumping the Super Game Boy 2 boot ROM.

In my previous blog post I analyzed a Gameboy cartridge with a DMG-BEAN-01 circuit board.

In this blog post we'll take a look at a slightly more advanced cartridge than we saw in the previous post.

In my previous blog post, I described the reasons why MBC chips are included in Gameboy game cartridges.

When I started developing Mooneye GB, I did the initial work in small gradual steps.

Recently my main hobby project has been Mooneye GB, a Gameboy emulator written in Rust.

I was recently looking for a simple Windows utility to turn off the screen, and I wanted it to be open source so I could compile it myself and be sure it doesn't do anything malicious.

I blogged last year about compiling Cyanogenmod for YW9300, but you might guess from the lack of updates that I never succeeded.

I've spent a huge chunk of my free time this week on learning Android internals by tinkering with an Android device called YW9300.

Introduction Using phantom types is a very simple technique that can be used to increase the compile-time safety of code.

Introduction Jawwa ZK Gritter is an open source library that can be used to add Growl-like notifications to ZK apps.

Introduction In part 1 I showed how server push and threads can be used to execute background tasks in a ZK application.

This is not a "pitfall" per se, but an implementation detail worth knowing.

Use cases Asynchronous UI updates are very useful, because they typically improve the responsiveness, usability and the general feel of user interfaces.

Many people, including Stephen Colebourne, have complained about some of the methods in the Scala collections API.

Spring objects are recognized based on their names It doesn't matter whether you use XML or Java config, a Spring scope is roughly like a Map<String, Object> structure.

I've finally managed to convert sbt-jrebel-plugin to SBT 0.9+.

As I mentioned in my previous post, ZK has a tendency to "just work".

I've been asked several times to present some of my opinions about ZK.

Overview of the challenge The biggest challenge in SBTEI is the most fundamental one: project metadata.

Scala is generally not backwards compatible, so matching Scala versions pose a challenge.

Comparing SBTEI and SbtEclipsify In addition to SBT plugins for Eclipse, there's also an Eclipse plugin for SBT called SbtEclipsify.

As an Eclipse user I've always been trouble by the lackluster support of SBT in Eclipse.

jQuery + ZK = A perfect match?

If you've used JPA, does this look familiar?

There's a very annoying IE6 incompatibility in ZK.

I was at first sceptical about JRebel, but after using it for a while, I must say that it's awesome!