Updating AmigaVision on the MiSTer—and the crash that taught me to hash everything

This post is part of the MiSTer series. Part 1 covers what MiSTer is and why this workshop runs two of them next to real hardware.

I went looking for one demo list and ended up doing a clean reinstall of my entire Amiga setup, chasing a corrupted disk image, and learning a checksum habit I should have had years ago. This post is the whole arc: updating an old MegaAGS install to current AmigaVision on a MiSTer, the version-hygiene trap inside the download itself, and the troubleshooting story that matters most—random red “Software Failure” Guru crashes (Error 0000 000B) that appeared right after the update, and the SHA-1 test that found the real cause.

AmigaVision, created by David Lindecrantz (Optiroc) and led today by Alex Limi, is the curated Amiga game and demo setup for MiSTer and real hardware—hundreds of games and demos, each with tuned per-title settings, behind one launcher. It used to be called MegaAGS, which is where this story starts.

Why I finally updated

While researching a post about the Amiga musician h0ffman, I learned that AmigaVision ships a demo list curated by the man himself—it appears in the launcher as Hoffman's Modern Picks, added in the 2026.04.16 release along with a new 060 Demos section and about four dozen new demos. I went to my own launcher to find it. It wasn't there. The banner across the top still read MEGA AGS 202X—the project renamed itself AmigaVision in 2025, so my install predated the rename by a comfortable margin. That settled it.

The before: MEGA AGS 202X branding, and no Hoffman's Modern Picks anywhere in the demo lists.

The one rule of AmigaVision updates: clean install, keep only your saves

The official documentation is unambiguous: every AmigaVision upgrade is a clean install. Each release changes core configs and settings files, so patching in place is unsupported. The one thing you carry over is your save data, which lives in its own separate disk image. Coming from MegaAGS, that file is called MegaAGS-Saves.hdf—rename a copy to AmigaVision-Saves.hdf (the project renamed it in 2025) and set it aside.

One distribution note worth being precise about: the AmigaVision team maintains the open-source build script, not the built packages—they point to archive.org's software preservation section for ready-made builds and are clear those aren't theirs. The package I used was AmigaVision-MiSTer-2026.04.26-r2.7z, about 4.9 GB. It unzips into folders that map straight onto the MiSTer SD card: _Computer, config, Filters, games, Presets, and Shadow_Masks each copy to the same-named directory under /media/fat/. Then you append the [Amiga] settings block from the official install page to the bottom of your MiSTer.ini—it adds a section, it doesn't overwrite your existing config.

Two traps in the copy step:

The saves clobber. The fresh games/Amiga/ folder includes a new, empty AmigaVision-Saves.hdf. If you copy everything blindly, it lands on top of your renamed save file and your progress is gone. Copy everything except the saves file, then put yours in place.

Binary mode. I load the SD card over the network—FTP into the MiSTer, no card reader involved, which also spares the FAT card the hidden junk files macOS likes to leave. If you do this, make sure the FTP client transfers in binary mode. ASCII mode silently mangles .hdf and .rom files. Remember this paragraph; it comes back.

Don't trust the History.txt—verify on the About screen

Here's the version-hygiene trap: the History.txt inside my 2026.04.26-r2 download topped out at an entry from October 2024. If I'd judged the package by its own changelog, I'd have concluded I'd downloaded a two-year-old build. I hadn't—the bundled doc file simply hadn't been refreshed. The launcher is the truth: after install, the About screen read AmigaVision 2026.04.26, and Hoffman's Modern Picks sat right where the release notes promised. If you're ever unsure which version you're running, ask the launcher, not the text files.

The launcher is the truth: About screen confirming AmigaVision 2026.04.26 after the clean install.

Then the crashes started: Software Failure, Error 0000 000B

Within the first evening on the new install, the red Amiga requester started appearing—frequently, and on seemingly random titles:

Software Failure.    Press left mouse button to continue.
Error:  0000 000B     Task:  40131EB8

Reading the Guru code is step one, and this one is a genuinely useful red herring. 0000 000B is a Line-F exception—the 68000-family CPU hit an instruction meant for a floating-point coprocessor it doesn't have. MiSTer's Minimig-AGA core emulates a 68020 with no FPU, so certain modern demos—the 060 Demos section is named for a reason—will legitimately throw this error on MiSTer. But that failure is title-specific: the same FPU-hungry demo fails the same way every time. Mine was random, across games and demos alike. Random crashes across everything on a freshly transferred multi-gigabyte disk image point somewhere else entirely.

The test that found it: SHA-1 both copies

One bad region in the main AmigaVision.hdf throws different errors as different titles read the damaged bytes—which looks exactly like random instability. AmigaVision's own troubleshooting puts image verification at the top of the list, and it takes one command per machine. One caveat from the official docs before you compare: launching the setup can write to the image, so the strict method is to compare a freshly transferred copy against the source (the MiSTer-side hash takes several minutes on a file this size).

On the MiSTer, from another computer on the network:

ssh root@<your-mister-ip>       (password: 1)
shasum /media/fat/games/Amiga/AmigaVision.hdf

(The F9 terminal on the MiSTer itself works too, but SSH from a desktop means you can copy and paste hashes instead of comparing forty hex characters by eye.)

On a Mac, shasum against your source copy; on Windows PowerShell, Get-FileHash -Algorithm SHA1.

Mine differed:

Source copy (Mac and PC, matching):  8e29361004b34f5bcbec69172b271c7179ab6b9a
MiSTer copy (sent over WiFi FTP):    17d6c95c5e71f67d6c4a0275e0aad5c97e2ba23d

The source was fine. The copy on the MiSTer was not. The culprit was the transfer itself: I'd pushed a multi-gigabyte image over a slow, marginal WiFi link, and it dropped bytes on the way. I'd even said “that took forever to upload” at the time, which in hindsight was the diagnosis.

The fix: delete the bad image on the MiSTer (don't overwrite it), re-transfer over a wired connection with the FTP client explicitly in binary mode, leave the saves file untouched, and hash again. Mine came back 8e2936…ab6b9a—a byte-for-byte match—and the crashes were gone. If a clean wired binary transfer still mismatches, suspect the SD card itself; AmigaVision's docs call a failing card the most common cause of all.

The re-transfer, verified: shasum on the MiSTer now matches the source byte for byte.

The other “error” that isn't one

While you're in the new install, you may see this in the AmigaDOS shell on nearly every launch:

EXECUTE: Can't open AGS:Run/Problematic/<Game> (OCS)[en]
object not found
execute failed returncode 10

This is noise, not damage. The launcher probes for an optional per-title override script in a Problematic folder; most games don't have one, so AmigaDOS reports “object not found” and falls through to the normal launch. The tell is that the game still starts. The one case where a returncode 10 deserves attention is if /media/fat/games/Amiga/shared/ is missing or empty—that folder is written to at launch time, and if it's gone, launches genuinely fail. Mine was healthy: fresh timestamps on its files matched my play session, which is how you confirm the pipeline is working underneath the console chatter.

(A postscript: the game named in that error message above kept catching my eye until I finally launched it. That turned into a whole tour—Best of AmigaVision: the shooters, over on Attract Mode.)

Console noise, not damage: the launcher probing for an optional override script that doesn't exist.

Video settings: use theirs

I run AmigaVision on both of my MiSTers—one on an LCD in the office, one feeding a CRT in the arcade room—and the recommended settings from the official documentation worked on both, including the CRT profile that was already in place. The project tunes per-title scaling and aspect handling as part of the curation; my advice is to take the settings the documentation gives for your display and leave them alone.

The checklist

If you take five things from this post: every AmigaVision update is a clean install, and only the saves file carries over. Verify your version on the launcher's About screen, not the packaged text files. Read the Guru code, but read it skeptically—0000 000B on a specific demo means it wants an FPU the core doesn't have; random crashes across everything mean a bad image. After any large transfer, hash both ends before you trust it. And transfer big disk images wired, in binary mode—WiFi FTP of multi-gigabyte files is exactly where corruption creeps in.

What I learned

The embarrassing part is that the diagnosis was in my own mouth the whole time—I said “that upload took forever” the day I did it, and then spent an evening reading Guru codes instead of listening to myself. The habit I'm keeping is cheap: any file too big to re-transfer casually is a file worth hashing on arrival. Thirty seconds of shasum when the copy lands beats an evening of chasing crashes that were never about the software.

Frequently asked

What does Amiga Error 0000 000B mean?
It's a Line-F exception: the program used a floating-point coprocessor instruction and the CPU has no FPU. On MiSTer's Amiga core (a 68020 without FPU), FPU-dependent demos throw it by design. If it happens randomly across many titles, suspect a corrupted disk image instead.

AmigaVision crashes randomly after an update—what do I check first?
SHA-1 the AmigaVision.hdf on the MiSTer against your source copy. A mismatch means the file corrupted in transfer (or on a failing SD card). Also worth ruling out: CPU D-Cache set to on in the core's system menu, which AmigaVision recommends leaving off.

Do I lose my saves when I update AmigaVision?
Not if you protect the saves image. Saves live in AmigaVision-Saves.hdf (formerly MegaAGS-Saves.hdf—rename yours if coming from MegaAGS). The new package ships an empty one, so don't let it overwrite yours during the copy.

Is “execute failed returncode 10” in AmigaVision a problem?
Almost never. It's the launcher probing for an optional per-game override script that doesn't exist. If games still launch, ignore it. If launches actually fail, check that games/Amiga/shared/ exists and isn't empty.

Further reading

• AmigaVision, by David Lindecrantz (creator) and Alex Limi (project lead): https://amiga.vision
• Official MiSTer install steps (including the MiSTer.ini block for your display): https://amiga.vision/download/mister
• AmigaVision documentation, including troubleshooting and the upgrade policy: https://amiga.vision/docs
• The AmigaVision build script (what the team actually distributes): https://github.com/amigavision/AmigaVision
• Arcade Game Selector, the launcher, created by Per Olofsson (MagerValp): https://github.com/MagerValp/ArcadeGameSelector
• The Attract Mode companion—Best of AmigaVision: the shooters, a visitor's tour of all 205: https://chicagolandretrotech.com/blogs/attract-mode/best-of-amigavision-shmups
• Part 1 of this series—what MiSTer is: https://chicagolandretrotech.com/blogs/news/what-is-mister-the-fpga-that-plays-every-atari-i-dont-own-and-some-i-do

I'm Jeffrey Mays. Bench Notes is where I write up the actual workshop work—burns, builds, repairs, and the occasional evening spent hashing a four-gigabyte file to prove the WiFi did it. Subscribe to catch the next one.