Recent content by dosdude1

Nice, I'll have to take a look at this one soon.

Well, because I haven't really had much time to work on it further, here is my working Classic Mac OS only version of the ROM as it is. In this form, it is so small that it can fit into any 64K or larger EEPROM, and of course has no EEPROM ID checks. So go ahead and give it a try; hopefully soon...

In theory, any of these Projovian ROMs can be modified in the same way once I get it figured out fully.

So, upon further analysis, it appears the reason they have done this weird "Use a stub NDRV that loads the real NDRV from a different location in the EEPROM" thing is because there is some weird bug with the VT6421 chip that prevents loading an option ROM past a certain length. The way I got it...

Almost done! Just gotta get the OS X side wrapped up, and we'll have a completely patched option ROM that will work with any EEPROM on any VT6421 card.

At the very worst case you can desolder the EEPROMs and flash them using an EEPROM programmer. Best case, you can simply flash on-board using Flashrom or my patched SeriTek updating utility under OS 9. I can’t find a datasheet for that EEPROM from a quick search, but if it supports 5V...

Yep, as mentioned, those weird solder balls that come from the factory on these PPC CPUs cannot simply be soldered to a bare pad, solder must be added to the pads before you're actually able to solder one of these CPUs with those solder balls. I've found that simply tinning the pads on the board...

I’d check the soldering... Looks like it may not be properly soldered. Best way to do it is to heat it with hot air until all solder is molten.

Yes, XPC7400 will go right on, and work no issues with the 3.3V L2 cache. Just need to change the VCORE voltage and PLL config resistors for desired clock speed.

Unfortunately, so far I have been unable to find a way to change L2 cache voltage on those ZIF CPU boards, so I normally use a 7400 to upgrade those. Last I remember when I messed with this, the L2 cache is connected to the same 3.3V rail as other components/circuits on that board, so segmenting...

12V is only needed to erase and program the AM28F010 EEPROM, which is why it cannot be programmed on-board (the board has no way of supplying 12V needed). In normal operation, the EEPROM runs at 5V.

Yep, you can install that EEPROM no issue, then flash it on-board. That EEPROM runs at 5V, just like the original, so no need to change any resistor position. The only case in which that is necessary is if you switch to a 3.3V EEPROM, which are normally designated with an “LV” in their part number.

A 5V-rated chip is what you want, unless your card has an option to change VCC voltage for EEPROM to 3.3V, in which case you can use an "LV" EEPROM. You don't want an EEPROM that requires 12V for erasing and programming (such as the AM28F010), as it can only be programmed externally in an EEPROM...

1. No need to replace Flash ROM on card in most cases, though some really cheap Chinese ones these days seem to be coming with AM28F010, which needs 12V for erasing and programming, so CANNOT be programmed on-board. This EEPROM will work just fine with my patched SeriTek ROM, but must be removed...

The best thing to do is flash my patched/compressed version of the SeriTek ROM, which can fit onto the original 128K EEPROM that a lot of these Sil3112 cards have. Though this RHC one should have a 512K EEPROM installed already if I'm not mistaken. Regardless, the same compressed ROM can be...