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Author Topic: iMac Holy Grail achieved ! Boot screens on 780m in 2011 iMac 27".  (Read 24437 times)
Rominator
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« Reply #45 on: September 29, 2018, 01:03:11 AM »

i got messaged that this thread was getting discussed at MR

i really hope to finish the rom, but I may be overlooking something simple

a perfect example is in the MR iMac thread.

A guy got a 21" from a Uni and  mistakenly says it is Firmware Password locked.

But he describes a folder with flashing question mark on boot.

This has been the "I can't find a boot drive" behavior as far back as I can remember.

but lots of helpful folks are outdoing themselves trying to help him get firmware issue fixed, an issue he doesn't have
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moopha
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« Reply #46 on: September 29, 2018, 09:19:22 AM »

Hey, Rominator, what size of ROM is expected in kilobytes?

My particualar 780M has a GD GD25Q20 EEPROM chip onboard, which capacity is 2048Kbit/258 Kbytes.
Is it enough to fit?
According to TechPowerUp BIOS database, none of 6 BIOSes exceed 164KB.
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Rominator
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« Reply #47 on: October 03, 2018, 09:53:18 PM »

yes, that should work
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moopha
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« Reply #48 on: October 04, 2018, 07:28:26 AM »

Got it, that's good


But ROM is still expected, is there any progress?
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Nenz
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« Reply #49 on: October 17, 2018, 01:11:04 AM »

Found DarwinDumper from original iMacs over here https://applelife.ru/threads/darwindumper-dampy-nastojaschix-macov.39174/
I wonder if this information from iMac 14,2 can help in understanding what need to be done?
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Rominator
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« Reply #50 on: October 26, 2018, 08:16:07 AM »

yea, sadly i have a lot on my plate right now, like enough for Christmas dinner already

don't know when i can get back to it, this is why i was looking for someone top work WITH
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Nick [D]vB
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« Reply #51 on: October 27, 2018, 11:16:16 PM »

Hi, I have some experience testing MXM cards with iMacs and have created several custom roms to substitute existing cards.  Mojave has obviously increased demand for newer cards supporting Metal so I started looking into that a few months back.  Sadly the A1312 iMacs have big problems initializing any AMD cards after the 6 series. For some unknown reason they require a soft reset before the PCI IDs are fully detected, and even then they flatly refuse to fire the back-light, which is annoying when you can actually see an image on the LCD using a flashlight!  The initialization problem seem like a real show-stopper, I suspect it's related to "Enduro" power management, the iGPU display output multiplexer, or most likely the way AMD started hashing certain values in their newer vbios?  I think we might just have to admit defeat on these.  Sad

Initially the Nvidia cards seemed more co-operative, but for their enigmatic DCB table...  I have the 680 / K5000 EFI loading with boot-screens on some external displays but I'm very curious to know how you fixed the corruption on the internal LCD??  No amount of futzing with the DCB table seems to help with that.  I've even tried modding the VESA tables, LCD centered timings, Display Port drive-strength values etc.   The EFI seems to have a BIT section to, maybe that needs some attention?  Am I getting warmer?    Undecided

I also tried getting some of the 2013 iMac's Kepler vbios to work on MXM cards, just naively under-clocking the memory wasn't enough as they seem to be structured quite differently, missing power tables etc?  I was hoping this might shed some light on the brightness control problem as they have a much simpler DCB table in comparison.  I did actually get the 3782 EFI to load but this just crashes the display driver so more research needed there.  I just posted about that in the 2080 thread, it could have implications for the MacPro to so thought you might find it interesting.  I'm away from home for the next week but was planning on getting stuck back into this soon.  Just let me know if I can help with anything, I still have an EEPROM programmer wired into my test machine so that should save us some time at least.   Smiley


* D300.jpg (241.81 KB, 1280x744 - viewed 213 times.)

* M380.jpg (235.23 KB, 1100x846 - viewed 234 times.)

* GK104.jpg (243.24 KB, 1100x800 - viewed 251 times.)
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Rominator
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« Reply #52 on: October 31, 2018, 01:35:20 PM »

my brother is a recovering addict who crashed his medical career and is currently stocking grocery shelves

I am not making this up

His version of Bob Loblaw's Law Blog sounds similar to what you have typed here.

What differences do you see in DCB? Which values?

Are you in LA? I'm stumble-home-drunk from the Kodak Dolby Theatre where they have that tedious awards show.
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Nenz
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« Reply #53 on: November 03, 2018, 10:17:56 PM »

Hi, I have some experience testing MXM cards with iMacs and have created several custom roms to substitute existing cards.  Mojave has obviously increased demand for newer cards supporting Metal so I started looking into that a few months back.  Sadly the A1312 iMacs have big problems initializing any AMD cards after the 6 series. For some unknown reason they require a soft reset before the PCI IDs are fully detected, and even then they flatly refuse to fire the back-light, which is annoying when you can actually see an image on the LCD using a flashlight!  The initialization problem seem like a real show-stopper, I suspect it's related to "Enduro" power management, the iGPU display output multiplexer, or most likely the way AMD started hashing certain values in their newer vbios?  I think we might just have to admit defeat on these.  Sad

Initially the Nvidia cards seemed more co-operative, but for their enigmatic DCB table...  I have the 680 / K5000 EFI loading with boot-screens on some external displays but I'm very curious to know how you fixed the corruption on the internal LCD??  No amount of futzing with the DCB table seems to help with that.  I've even tried modding the VESA tables, LCD centered timings, Display Port drive-strength values etc.   The EFI seems to have a BIT section to, maybe that needs some attention?  Am I getting warmer?    Undecided

I also tried getting some of the 2013 iMac's Kepler vbios to work on MXM cards, just naively under-clocking the memory wasn't enough as they seem to be structured quite differently, missing power tables etc?  I was hoping this might shed some light on the brightness control problem as they have a much simpler DCB table in comparison.  I did actually get the 3782 EFI to load but this just crashes the display driver so more research needed there.  I just posted about that in the 2080 thread, it could have implications for the MacPro to so thought you might find it interesting.  I'm away from home for the next week but was planning on getting stuck back into this soon.  Just let me know if I can help with anything, I still have an EEPROM programmer wired into my test machine so that should save us some time at least.   Smiley

What is the software "nVidiaInfo" is used on your screenshots?
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Nenz
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« Reply #54 on: November 06, 2018, 03:08:57 AM »

Can this help anyhow?


* S1.png (132.7 KB, 1720x1442 - viewed 222 times.)

* S2.png (28.09 KB, 894x796 - viewed 163 times.)
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Tpluth
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« Reply #55 on: November 25, 2018, 09:55:20 PM »

Did Rominator fall off the face of the earth?

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overshoot
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« Reply #56 on: November 29, 2018, 03:52:37 PM »

Seems like Duke already got the GTX 660M and GTX765M working on the A1312 iMac based on this Louis Rossmann stream:

https://www.youtube.com/watch?v=0w1knwLjULs

Check a 2:08:00, he's talking about it.
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Tpluth
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« Reply #57 on: December 06, 2018, 05:50:03 AM »

He mentions getting the Dell 1GB 6770M working with a modded VBIOS, but nothing about the 780M.

Does anyone have modded VBIOS for GTX 765M and/or 780M that gets the thunderbolt ports working?
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overshoot
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« Reply #58 on: December 07, 2018, 04:27:18 AM »

Thanks for clarifying
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FlorisVN
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« Reply #59 on: December 09, 2018, 05:37:24 PM »

He mentions getting the Dell 1GB 6770M working with a modded VBIOS, but nothing about the 780M.

Does anyone have modded VBIOS for GTX 765M and/or 780M that gets the thunderbolt ports working?

As far as I have seen, with testing GTX765m, thunderbolt looks to work fine.
I have not tested a thunderbolt device yet, but I don't see why it should not work..

I got only 1 external display working, using an TB-HDMI adapter..
Second thunderbolt/mini dp output was not working at all for a second monitor here..

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