QUOTE(nartac @ Jul 11 2008, 02:21 AM)
I have successfully installed a white Duox2 chip with cromwell/flashbios. I read multiple tutorials on installing hacked bios and all of them mentioned installing Evox bios for v1.6 xboxes. I would prefer to install xecuter bios X2.5035 for v1.6 as it's newer and I like xecuter bioses. Is there a problem in using xecuter bios instead or do I have to use Evox bios?
Thanks in advance for your inputs.
Does the Duo X2 have 2 banks of 256k or it can work as 1 bank of 512k? X2 5035 is a 512k sized bios. Apart from that, I remembered something about the weird behavior of the xcalibur and memory timing stuff that only a 1.6 specific bios will do properly... but I can't remember where I read this anymore. Somebody else will probably be able to say more on this topic?
EDIT: Credits to the respective contents owners
Found this on eurasiawiki and smartxx's forum:
franz (aka hamtitampti)
To end the controversy from the last few days. Some facts: Team SmartXX knew about a "1.6b"(Improper terminology) for a long time, but nobody wanted to listen. Initially, the Xbox PCB was designed for Samsung and Micron SD-Ram chips. However, MS was mainly using Samsung Memory. When the first 1.6 boxes came, we saw a different RAM pad, which made it possible to change the RAM and use even other vendors. After a quick analysis, I found out, that this was more of a Signal HF termination issue rather than an "anti-Ram upgrade".
After analyzing the 5838 bios, I saw, that the memory timing table had more entries.
What are these entries?
1: to use RAM from different Vendors
2: to use buggier ram
If you have a PC, you can change Ram timings, from Fast, to slow or failsafe.
I personally have had this issue in Cromwell already, when we had "crazy boxes." After searching for weeks I found out, when we took timing dumps from an "optimistic" box.
The box has a table with ram timings. During the startup period, Ram is in fail-safe mode and very slow. To get optimum performance, MS makes a small memory diagnostic and then decides which mode they will set the ram to based upon this diagnostic. Strangely, this was only in the beginning of the bios and in another occurrence later in the BIOS this "choice" was not included and they simply used static values.
MS has basically used "high quality" ram so far.
But to lower the costs, MS is now buying everything, even class B and C ram. These parts are outside tolerances. Every production of eg. CPU is the same. If you buy eg. a 2.4 Ghz CPU, it is essentially the same as a 2Ghz CPU. But after the production, you see some CPUs failing at higher rates, so they are reconfigured and sold as a slower CPU.
10% = 3.0 Ghz Cpu
50% = 2.5 Ghz Cpu
40% = 2.0 Ghz Cpu
This is why overlocking sometimes works and sometimes doesn't.
The same process applies to RAM. The Startup diagnostic diagnoses the ram, and then looks at which timing is best, and then they dump this information into the chipset. Like a Bios on the PC.
As this wasn't enough on xbox 1.6, MS also changed the layout of the EEProm and the Xcodes during Startup read from the EEprom. The last 0x20 (or 0x30 I not remember for sure) are then read out by the X-codes and the values dumped into the chipset. These values are very likely to be the "vendor specific" inits for the RAM to put it into failsafe mode. They are created during Xbox Testing (memory testing) at MS Fabrication.
They have 3 main advantages:
* Use any ram they find
* Buy cheaper ram (Ram is a very expensive product)
* Have optimum performance on the system
Why is this so important? Those of you who know anything about PC architecture can tell you the random bugs that invalid memory timings can cause. If you configure your Ram too fast or outside parameters, your Ram might not store information correctly or loose information. So during operation, and temperature changes, the ram looses information or might not even works correctly from beginning and it leads to sporadic symptoms like: crashs, hangs, boot deny, working/nonworking, freezing after a little while, freezing after a long time, and all kinds of various effects.
If you take a modern PC Ram module, you will find a small SPI/I2C EEprom called the SPD. If the SPD falls off or ceases to function your system still runs but not as stable. Since the Xbox does not have an SPD EEprom they store the information inside Kernel and the central system EEprom. --- The M8 BIOS uses a self written 2bl loader, and I think, and not the full ram timing table. Evox M8 bios, uses the same table(offset 0x1c00) as 5713 bios(and others). But in 5838 this table was dramatically expanded. (surprise!) So M8 Bios simply used the timing table which they had from history and ignored the possible appearance of lesser, different, cheaper Ram.
This is possible to fix, and I think this will be done very soon. I hope they will, because the Ram settings are completely false and can lead to permanent RAM damage.
"M8 can kill your Xbox ..."
(sorry for english, i have tooth-ace and i already wantet to go home since 2 hours)
EvolutionX released Evox M8+ BIOS featuring added support for xbox 1.6 with Hynix RAM circuits (aka xbox 1.6B). M8plus.bin is a new BIOS based on the latest 5838 kernel, and has the same features as M7, it will work on XBOX versions (1.0, 1.1, 1.2, 1.3, 1.4, 1.5). M8plus_16.bin is also based on the 5838 kernel and has the same features as M7. It will ONLY work on XBOX version 1.6 and 1.6B. EvolutionX thanks Team Xecuter for bringing attention to this issue and Franz of Team SmartXX for uncovering the problem.