Óscar Toledo G. Profile picture
➀MSX/Atari/CV/Intellivision/SMS game dev ➁Princess Quest in Evercade Intellivision ➂Knight of boot sector games ➃IOCCC+JS1K winner ➄IntyBASIC creator ➅Author

Jan 30, 2023, 7 tweets

If you have an old #motherboard stuck saying "Checking NVRAM..." (typically K5/K6/Pentium 1 or 2) there is no NVRAM chip, instead it is unable to write its own Flash BIOS to save data, because it exceeded the maximum number of writing allowed (yep, you used it 10,000 times)

To solve this you need to order the AT29C010A, this Flash chip is erasable in 256-byte pages AND it can still be accessible to execute code. My first try was the AM29F010 but it doesn't work for this.

Now you should download the BIOS ROM file for your motherboard model, and program it to the AT29C010A

Now you put the new Flash chip on the motherboard taking care of the orientation.

And now it works! By the way, the AT29C010A now is good for 100,000 cycles.

If you search Twitter for "Checking NVRAM" you'll see it is common trouble, and many people thought erasing the CMOS could help. I've tweeted this, so people will be able to find this thread, and solve this long-standing problem.

Wow! This thread went amazingly popular, and I reached 2,500 followers! So now a shameless plugin per Twitter tradition, probably you'll be interested in my books Programming Boot Sector Games, and More Boot Sector Games, available from Lulu and Amazon 😉

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