About firmware versions and overclocking:
I've been doing some serious digging!!!
...
YOU ask:
How do you get to 768, please explain
May 26 and Aug 12 firmware-versions are overclockable either from SSH into machine and changing the file "/config/cgminer.conf" or from Chrome using "Inspection" for the field where you choose "frequence" (May 26 version) alt. "mode" (Aug 12 version) on page "Miner configuration - Advanced settings" and for the May 26 version ofcourse you just choose the frequence here you wan't just like God intended !
THIS is how:
" ... SSH into machine and changing the file "/config/cgminer.conf" or from Chrome using "Inspection" for the field where you choose "frequence" (May 26 version) alt. "mode" (Aug 12 version) on page "Miner configuration - Advanced settings" ... "
I use the program "Putty.exe" on windows 10 machine to SSH into my z9 mini.
Step:
0. Start Putty.exe and input ip-adress for machine to SSH into. (For my z9 mini in my home network ip = 10.0.1.101)
1. Press "Enter"-button
2. First time putty.exe SSH into a machine it ask's you to approve that machines ssh_host-key
3. Press "Yes-button" on pop-up window and now the terminal window opens where you type in your commands
4. root
5. Press "Enter"-button
6. root (if factory default or use the password you've changed to when login in to your z9 mini)
7. Press "Enter"-button
8. cd /config
9. Press "Enter"-button
10. vi cgminer.conf (file cgminer.conf opened up in the "vi"-editor)(BE CAREFUL - google vi editor and learn howto use it)
11. Press "Enter"-button
12. use "arrow"-keys and move down to "bitmain-freq": "500"
13. Press "i"-button (this is for insert-mode) (be VERY careful NOT to change/delete/add anything else but...)
14. change "500" to "768"
15. Press "Esc"-button (but ONLY once)
16. :wq!
17. Press "Enter"-button
18. cat cgminer.conf
19. Press "Enter"-button
20. Now you see the text in cgminer.conf and can verify that you have changed to "768" and nothing else has changed.
21. /etc/init.d/cgminer.sh restart
22. Press "Enter"-button
23. Now your z9 mini reboots and voila !
This will ONLY work if that specific z9 mini machine can handle 768 MHz !!!
My specific z9 mini will NOT run solid on 775 MHz or above.
IF I go above 768:
At 775 it starts up all three chains without errors but after 5-15 minutes or so I will see "KSol/S(RT)"-value going down slowly and continue down and I will go into page "Miner configuration - Advanced settings" and choose 750 and then press "Save&Apply"-button at bottom right corner.
z9 mini restarts at 750 MHz
(Going to high and it will not even start up all three chains !)
Now I go thrue step 0-23 and again set it to 768 MHz.
I've done this a few times and now tested and know that MY specific z9 mini can handle 768 MHz but nothing above that.
Now I just let it run and run and run at 768 MHz.
Only time I restart is if I change mining pool or try any different settings at some miningpool and if thunder and lightning outside I will unplugg my z9 mini PSU from the 240V connector in my wall.
BUT it's easier to use Chrome to change the value to 768 or whtever
(There are youtube video and other poeple on this forum that already explains how that is done!)