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ayilm1 / gMUXBypass

Bypass graphics multiplexer on 820-2914 and 820-2915
GNU General Public License v3.0
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will this possibly work on 820-2850? #4

Open protocold opened 4 years ago

protocold commented 4 years ago

I compared the gmux pin out of the 820-2850 (2010 15") with 820-2915 (2011 15") on schematics and found out that the pins are the same (except some minor naming differences).

Would this actually work on the 820-2850? I have a few with defective GPU (no, it isnt faulty C9560 tantalum capacitor)

ayilm1 commented 4 years ago

Possibly? I haven't compared them myself but if you have, your decision if you want to try and flash it. Sounds like you've written the boards off anyway given your reluctance to replace the GPU. So they're in the scrap heap either way right? As far as BGA replacements go, the FPGA is also 'friendlier' compared to the GPU should you want to undo. Also note that if you want brightness control, there's no guarantee of the PCH's microvia being in the same location since it's a different generation.

protocold commented 4 years ago

Tried and it doesnt work. After flashing the logic board, the fan will just spin up and down. But the problem isnt about JED file but 820-2850 itself, because:

A)If i flash the original GMUX backup from other thread for 820-2915 onto this board and it will work and boot up OK, so the gmux bypass firmware developed for 820-2915 should work in theory.

B)If I disable the GPU power R8911 but keeping the original gmux firmware on this board it will behave the same, also fan spin up and down. Probably the SMC is detecting GPU is NOT powered on and it is power cycling the board?

Ibrahim-monem commented 3 years ago

Does anyone have gmux file for apple 820-2850-A uma convertion with lattice ?

itank commented 1 year ago

What about macbook pro mid 2012 with 820-3330 board ? I've asked one company which are making software mod and they said it is possible.

ayilm1 commented 1 year ago

What about macbook pro mid 2012 with 820-3330 board ? I've asked one company which are making software mod and they said it is possible.

As far as the signals being affected by this configuration (LVDS, LVDS_IG, and power supply enables), it looks like it should behave.

P3V3GPU_EN->EG_RAIL1_EN GPUVCORE_EN->EG_RAIL2_EN P1V0GPU_EN->EG_RAIL3_EN P1V5FB1V8GPU_R_EN->EG_RAIL4_EN

The L_BKLTCTL output of the PCH also appears to be on the same ball (P45), though it is a different chipset, so the microvia on the interposer may not be in the same location. Unfortunately, as with the 2915, P45 is not fanned out to a testpoint. However like the 2915, you do have a testpoint for LCD_BKLT_PWM on the same side as the PCH next to C9623. So you don't have to run a wire around the board like I did.

Can't validate this any further than this, but it looks feasible on paper. As usual, standard "not responsible if SHTF" disclaimers. There may be other differences in the SMC firmware that check for magic packets on the LPC etc that keep the system from booting if the CPLD isn't stock/modified with the knowledge of such mechanisms. Wouldn't put it past a mob like apple.