Thanks @sidehack for your great learning sesson about reading forum!  
When I read the post of neowhere on this page 78 - the problem seems to be still there! And your answer "try adjusting the voltage a little bit" sounds not like the final solution....So why I should read page 23...37...56...?

I read page one, found issue depening links and get not the right answer... Also I googled my problem and hit some pages, here in the forum, in the middle between page 1 and 78... Problem is only get more questions, but no answers... after 2 replies, the forum changing in a totally different theme. Thats the problem of this one-thread - al lot of themes and issues in one chain.... So I need first of all 2 weeks exploring the forum....

But back to my ZOMBIE issue. I made the following steps and seems to get it solved. I tested it only with my two 2Pac's, named #1 and #2 and get no ZOMBIE stats at the moment.
1. Plugin #1 on power supply, only with the customized soldered power lines.
2. Measuring the ASIC-voltage at the two capacitances and adjusting it to 0.68V and 0.7V (slight diffenrence of 0.01..0.02V still present). --> voltage level recommended for 200..250Hz in the manual.
3. Plug off #1 and plugin #2 on power supply (seems to be importand that every stick is alone on the power supply --> if not, one gets into zombi (asymmetric asic voltage)).
4. Measuring the ASIC-voltage on #2 at the two capacitances and adjusting it to the same level and difference as #1 = 0.68V and 0.7V (slight diffenrence of 0.01..0.02V still present). --> seems, both stick should use the same asic voltage levels, despite there should independent from each other

After this symmetric adjustment of both sticks, I made the following observation:
5. starting cgminer without any plugged 2Pac.
6. When I plugin #1 to the power and then to usb-hub (data connection), this miner starts working (LED flashes).
7. when I add the second stick #2 to the power and to the usb-hub, one of the sticks getting into zombie, most of the time the first plugged stick gets into zombie, second starts mining --> seems to be a voltage volatilitiy during plugin or something....ASIC-voltages of the zombie sticks gets immediatly asymmetric...the first working stick seems to get a problem, when the second is plugged to the power supply.

So I made the connection in the following way:
8. power off power supply and usb-hub (are on the same power connection).
9. connect both sticks to the power connection and to the data connection (usb-hub).
10. power on power supply, so sticks starting at the same moment, also the connection via usb-hub
11. both sticks are getting recognized and starting work with running cgminer.
At the moment this setup runs without any ZOMBIE stats at 200MHz (tested only for the last night and some hours today).

But there is still a problem - the Raspberry gets freezed sometimes (the whole Raspberry, not only cgminer).
I read the link at page 1 about kernel debug mode. But not modified and tested at the moment.

Hello Guys,
I'm new here. I didn't read all the 78 pages...to much, but get the same problem discussed on page 78 - different core voltage.

I'm using a Raspberry Pi3 with Raspbian Stretch. Installed succesfully cgminer (vthoang) and driver, as described in the Gekko 2Pac manual. I have 2 Gekkoscience 2Pac available.
Regarding the power consumption, I'm using an older frontpanel 10xUSB2.0-hub, which I customized to connect it directly to a external power supply. Data connection is soldered to connect to Raspberry USB. I checked every USB-connector of the Hub via Memorystick to the Raspberry, every connector works (data connection is present).
Additionally, I soldered separate power wires on the USB-Jack of the 2Pac's (on the solder pins on the 2Pac-Board). So I can connect the 2Pacs directly to the power supply - no bad connection resistances over the USB-Hub and so on. The power supply is at the moment a laboratory power supply, which can support 3.3A maximum.

I'm starting cgminer with plugged off 2Pac's. After the start, I plug in one 2Pac (hotplug, but first plug in connection to power supply). 2Pac gets recognized and starts working, for example at 200MHz (LED flashes). When I measure the vcore on the two capacitances, I have 2x0.67V (symmetric, only small diffenerence of 0.02V). Single miner works stable during the night with no hardware errors.

When connect the second 2Pac only on the power supply, I can measure also a vcore of 2x0.67V (symmetric). Then I plug in the USB-connector to the hub (data connection). 2Pac gets recognized, but after some minutes he is named as ZOMBIE. When I measure then the vcore, I measure 0.52V and 0.88V for example, a total asymmetric behaviour. Why? Is there a problem with the voltage regulator or some single items on the board (capacitance, resistor, diode)?
When I plug off this stick from the Hub and from the power supply and connect it only to the power supply (after some minutes), the vcore is still asymmetric. Only after a longer time, vcore is symmetric again.

I marked the 2Pacs with numbers - #1 and #2. I tested it in different sets. When #1 is plugged in and works, #2 gets into Zombie with asymmetric voltage. When #2 is plugged in and works, #1 gets into Zombie with asymmetric voltage. Seems to be no hardware issue on the sticks... some kind of software failure.... I will also test a more powerful power supply - but current limit was not detected yet (2.98A with two sticks at start).
Read a lot of this issue here in the forum and the internet, but there seems to be no solution, yet.