Hacker News: dmonterocrespo

New comment by dmonterocrespo in "[dead]"

dmonterocrespo — Mon, 12 Oct 2026 19:15:33 +0000

Castlevania: Symphony of the Night (PS1) running on an ESP32-S3 microcontroller, in a handheld I built around a XIAO ESP32S3 Sense. The game's decompilation compiled straight to the chip. The game runs at full speed, 60 fps

New comment by dmonterocrespo in "PS1 Game on ESP32-S3"

dmonterocrespo — Mon, 12 Oct 2026 19:13:27 +0000

Yes, I liked the challenge because it was the cheapest and smallest ESP32 S3 out there. I think more PlayStation 1 games could be ported to that mod; I was even able to port Castlevania: https://github.com/davidmonterocrespo24/sotn-decomp

New comment by dmonterocrespo in "Show HN: PS2 games statically recompiled to WebAssembly"

dmonterocrespo — Mon, 12 Oct 2026 13:18:42 +0000

This is exactly the approach we've been taking with Metal Gear Solid. We’ve been working on a fork of mgs_reversing (which is targeting 100% matching decompilation of MGS Integral) to bring the game natively to microcontrollers: https://github.com/davidmonterocrespo24/mgs_reversing

Instead of high-level emulation, the decompiled C source is compiled directly to Xtensa machine code for the ESP32-S3. We replaced the PlayStation SDK/GPU/GTE with custom software routines, running on a DIY handheld built around a Seeed XIAO ESP32-S3 Sense.

To speed up development without constantly flashing hardware, we run the compiled firmware image directly inside a browser-based hardware simulator CLI (velxio-cli) to verify serial outputs and execution in seconds.

Having 100% matching C code makes native ports to embedded platforms completely feasible without relying on heavy JIT/interpreter glue.

PS1 Game on ESP32-S3

dmonterocrespo — Tue, 29 Sep 2026 19:10:33 +0000

Article URL: https://www.reddit.com/r/embedded/s/vkgFuZviRD

Comments URL: https://news.ycombinator.com/item?id=49898805

Points: 5

# Comments: 3

New comment by dmonterocrespo in "[dead]"

dmonterocrespo — Mon, 28 Sep 2026 00:46:39 +0000

I ported the decompiled C code of the 1998 PlayStation version of Metal Gear Solid to the ESP32-S3.

The game code compiles directly to Xtensa machine code, with the PlayStation SDK, GPU, GTE, CD drive, scheduler, and controller replaced by software layers.

It runs on a Seeed Studio XIAO ESP32-S3 Sense with 8 MB PSRAM and microSD.

The post goes into the porting process, memory layout, scheduler, software rendering, debugging, and the bugs that took the most time to find

New comment by dmonterocrespo in "Apple iPod Engraver (2019)"

dmonterocrespo — Sun, 13 Sep 2026 23:20:37 +0000

It's a fork of https://github.com/devos50/qemu-ios. The idea is to reverse engineer the Samsung S5L8702 SoC to emulate the real system.

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 19:49:18 +0000

We can all combine our own knowledge, enthusiasm, and AI to do amazing things. It's like using better computers with better processors. For programming, I could perfectly well use a PC from 2001.

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 19:47:35 +0000

I admire the entire community behind reverse engineering iPods. I'm active in various community channels, sharing information with them. I wouldn't be an engineer without using the tools and knowledge of those who came before me. The translator (I speak Spanish) changed the text a bit, and some words came out in all caps, but I've already corrected the names.Thanks to everyone for taking this to the next level!

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 18:42:03 +0000

https://www.reddit.com/r/programming/comments/1js8gqz/emulat...

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 18:38:32 +0000

Here are some details about how I made the iPod Classic 6G emulator and what I encountered along the way: https://x.com/DMonteroCrespo1/status/2095882094455009695

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 18:30:51 +0000

I think the community is very close to achieving it

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 18:30:07 +0000

Hi, I wrote that note by hand; I didn't use Claude. The hypotheses were based on the fact that other emulations used different paths to reach the playback device. For example, I analyzed Rockbox to see how they managed to play music on this chip. I did use Claude and Gemini to investigate and create the emulator code

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 18:23:41 +0000

Some improvements are still needed, but the idea is to run the original Apple firmware without modifications. I'd like to be able to run it on a Raspberry Pi Zero someday... a very thin layer will lift the iPod Classic 6G emulator

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 18:20:12 +0000

Even though I used AI, it took me months to decipher parts of the emulation. I had to study, and I loved learning things I didn't know. It's also a very beautiful learning path; everything related to technology is magical. Engineers from all over the world are trying to revive the iPod and products that are no longer commercially available.

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 18:17:37 +0000

I used AI, and I mention it in the post. I'm also an engineer at IBM, and I know a bit about operating systems and embedded systems, which helps me understand and decipher parts of the iPod. I also have a small workshop where I was able to repair an iPod that had been broken for a few years. The community is truly amazing, and it supported me in subsequent research such as freemyipod and https://github.com/devos50/qemu-ios

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 18:14:53 +0000

I didn't know that, it's a good fact. When I had my iPod 6G, that album art animation looked amazing.I haven't been able to unlock it because it has many upgrade directions that I haven't been able to decipher

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Fri, 11 Sep 2026 18:08:53 +0000

I saw your work and I thought it was excellent; that's another step I want to take: being able to run the games and the cover flow! We're one step away from making the iPod free forever.

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Tue, 08 Sep 2026 16:44:53 +0000

One of the things that gave me a lot of trouble was unlocking the music player. Reverse engineering it was really difficult. I investigated many possible variations, tried searching on https://freemyipod.org for memory register information, but there was nothing for this particular iPod that could help me with the music player. Now I'm trying to unlock Cover Flow, which is something I really liked the first time I saw it on my iPod.

New comment by dmonterocrespo in "iPod Classic 6G in QEMU"

dmonterocrespo — Tue, 08 Sep 2026 14:54:57 +0000

I've been developing a QEMU emulator for the iPod Classic 6G (Samsung S5L8702) that boots the original, unmodified Apple retailOS. Navigation, the disc, the screen, and the music library worked for a while, but the music player appeared partially rendered and without sound. There were four different errors, and the last one was my fault in a way that I found amusing enough to write about.

For months I've been trying to emulate the iPod Classic 6G I have in my drawer, without success. After a long time, I finally managed to get it running, although it's still somewhat rough. In QEMU, I managed to boot the original, unmodified Apple retailOS. Navigation, the disc, the screen, and the music library worked for a while, but the music player appeared partially rendered and without sound.

One thing we already know is that the firmware is from Apple and is encrypted, so there's no legal download. I have an iPod Classic 6G from 2008. With the help of Claude Code, I was able to create code to extract it using emCORE. I extracted the contents of the flash memory and decrypted the image myself.

and the boot ROM cannot be read from the running device. I confirmed the latter the hard way, and along the way, my iPod restarted several times (pressing the center and menu buttons for 5 seconds to restart it).

There is no datasheet for the SoC. Each model register that allows unlocking some part of the guest is derived from a write operation performed by the guest itself,

Code and notes, including the ~16 hypotheses I had to retract along the way

iPod Classic 6G in QEMU

dmonterocrespo — Tue, 08 Sep 2026 14:54:57 +0000

Article URL: https://www.reddit.com/r/emulation/s/VL4Au2HGxq

Comments URL: https://news.ycombinator.com/item?id=49611240

Points: 162

# Comments: 47