Updated Guide on How to Mine Both BTC and LTC on Gridseed 5-chip GC3355 ASIC

22 Mar


When we’ve made our previous guide for dual mining BTC and LTC on a Gridseed 5-chip GC3355 ASIC we’ve only had an earlier revision of the miner that used CP2102 USB to UART Bridge Controller. Now that we already have a newer revision with the STMicroelectronics Virtual COM Port we have decided to update the guide with information on how to Dualmine on these ASIC devices. Note that we do not recommend using these devices for dual mining mode, but for Scrypt only mode instead, but you are free to decide for yourself. The advantages of using Scrypt only mode are the low power consumption and heat, the ability to overclock higher, including with a voltage modification and a choice of multiple more up to date software miners. Note that the only way for the moment to use the Dual Mining mode on the Gridseed 5-chip GC3355 ASIC devices is to use the special version of cgminer 3.8.5 for BTC mining (SHA-256) along with the special modified version of cpuminer for Gridseed for LTC mining. Due to the way that the Dual Mining mode is realized on these ASICs using a more recent version of cgminer or bfgminer for LTC (Scrypt) mining on these devices along with the cgminer for BTC mining is not possible at the moment.


– Open up Windows Device Manager and go to the Ports (COM & LPT) and note the COM port that is written behind the STMicroelectronics Virtual COM Port driver
– Download and run the latest version of Zadig
– From the Zadig interface select Options and choose List All Devices
– From the Dropdown list of devices select STM32 Virtual COM Port and click on Replace Driver with the WinUSB driver selected
– Download the dualmining package that we have prepared for windows that contains cgminer 3.8.5 for BTC mining and cpuminer for LTC mining
– Edit the BAT files for the two software miners included in the archive with your settings for BTC and LTC mining pools
– In the LTC-START.bat file you will see an option “gc3355=\\.\COM4”, here you need to change the COM port number to the one you have seen in the device manager before updating the driver with Zadig to use WinUSB
– First you need to start cgminer 3.8.5 for BTC mining, wait a few seconds until the software starts up and connects to the pool and starts working
– Then start the cpuminer for LTC mining, note that you will need to wait for some more time here before the miner connects and starts working, but it it takes more than a minute maybe something is not right

If you still haven’t used cpuminer for Gridseed you should know that the software does not report local hashrate, so the zeroes you see are normal, it is actually working and sending shares. Also note that when in Dual Mining mode you will not be able to overclock the device as high as when only in Scrypt mining mode, so it is normal to be getting lower hasrate. As we’ve already said, we do not recommend the Dual Mining mode and suggest to use these ASIC devices for Scrypt mining mode only, especially if you want to run multiple devices.

Download the DualMining package for BTC/LTC mining on Gridseed 5-chip GC3355 ASIC for Windows…

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37 Responses to Updated Guide on How to Mine Both BTC and LTC on Gridseed 5-chip GC3355 ASIC

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March 22nd, 2014 at 20:27

Is there a way to have LTC mining done through cgminer, and BTC mining done through cpuminer? Kind of the reverse of how you have it?



March 22nd, 2014 at 20:48

No, it is not possible.


March 22nd, 2014 at 21:42

Is it possible to fork the Vertcion mining version of cgminer to make it work with the Gridseed ASICs?


March 22nd, 2014 at 21:44

No, these devices are only capable of Scrypt or SHA-256 mining.


March 22nd, 2014 at 23:10

ace thanks for the updated guide, if only I had this 24hrs ago :P still the old one was useful to a point. One question – when running in dual mode. Can u set a different frequency for both sha and scrypt. Say 600/800 ? I have experimented a bit and it seems to work…


March 22nd, 2014 at 23:13

ps, if you forgot your com number try “gc3355=STM32″ even works for multiple instances with multiple devices… handy if you cant be arsed to start again!


March 22nd, 2014 at 23:49

Will, thanks for the tip. We’ve noticed you could set different frequencies, though not sure if the device actually runs with different ones for BTC and LTC. The fact that cpuminer makes it hard to guess what the actual hashrate is doesn’t help.


March 23rd, 2014 at 04:49

I can only get two grid seeds to run. I seems to be a driver issue or issue with zadig. The seeds show up as stm32 in the device manager, but cgminer gives an error and refuses to start. Cpuminer “sees” the seeds and sends work, but no of it seems to come back. It just detects new stratum blocks.

Has anyone been able to run more than two? Thanks


March 23rd, 2014 at 06:10

Mike, there are people running 20 and even more of these, so yes.


March 23rd, 2014 at 07:14

I can run a bunch with bfgminer, just cant get more then 2 of them to dual dig on windows 7


March 23rd, 2014 at 10:55

@Mike I have 3 dual mining on win8 and win7. I have found that the 750 freq on both BTC and LTC is best. This is what I did…

Replace the STM32 drivers with USB ones with zadig. Open up zadig after finished and make sure the left box now reads the same as the right on all stm32 devices

Run an instance of LTC cpuminer for each device. then close them, this is just to get the -dual working… i struggle to get them back to single and have to fire up a cpuminer with no -dual in it to get them back to single…

close all the cpuminers…. start the BTC miner… If it doesnt detect devices, close cgminer and reopen until you do… take your time…

then start 1 ltc cpuminer instance for each device…

works for me every time, I have moved the 3 devices over two 3 different machines now.. Temperamental things, the build quality is a bit crappy and you will find that they run at different speeds. They also seem more prone to nonce errors when running in dual. reduced clock freq will aid this…

happy mining.


March 23rd, 2014 at 13:31

@ Mike – Here’s what works for me with 3 gridseeds (after replacing STM with WinUSB using Zadig): All Gridseeds unplugged. Set –hotplug=5 in cgminer bat. Start cgminer. Plug power into each gridseed. Plug USB into each gridseed one at a time waiting until cgminer sees each one. All will be working in cgminer now. Then start one cpuminer for each gridseed.

@ Will – What kH/s (from pool) are you getting with cpuminer at 750 freq? In dual mode, I’m getting less than 300 kH/s (scrypt) each with 600 cgminer & 850 cpuminer.

@ admin – Can we set individual frequencies by gridseed serial number in this build of cgminer 3.8.5?


March 23rd, 2014 at 15:22

Miner, no individual frequency cannot be set for different miners in cgminer 3.8.5, though it could probably be implemented…


March 23rd, 2014 at 15:59

Thank’s I’ll give that a try. device detection seems to be my problem.
I am happy with the speed I’m getting on the ones that I was able to get running in dual mode. I have about 9gh/s at 750 and 320kh/s at 850. I was getting a lot of scrypt errors at any speed until I lowered the btc to 750mhz.


March 23rd, 2014 at 16:46

Will & everyone – thanks for the info re: all at 750. It looks like everything is a bit faster now. I don’t think the devices understood different frequencies for cgminer and cpuminer. I had them at cgminer 600 and cpuminer 850 and the power consumption at the outlet with a PC was 180 watts. Now, at at cgminer 750 and cpuminer 750 power consumption is 218 watts.

cgminer 800 works but cpuminer doesn’t like 800. 775 might be the magic number but I don’t know if that is available in this build of cgminer.


March 23rd, 2014 at 17:58

Guys do note that when you run the cgminer 3.8.5 for BTC mining it does set the operating frequency for both the BTC and LTC mining, these are set separately, but cgminer 3.8.5 sets them to be the same. After that when you run cpuminer it can change only the LTC frequency. When you run dual mining mode the highest problem free (no HW errors) operating frequency for the LTC cores is lower than when running the miner in Scrypt only mode.

The cgminer 3.8.5 for Gridseed BTC mining does support the following frequencies: 250, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850 and 900. Setting any other frequency will default to 600 MHz. There is not point in frequencies higher than 900 MHz as you would probably not be able to get the device stable in dual mining mode at even 800 MHz. It is not wise idea to dualmine on voltmoded devices as this might get the VRMs of the ASIC too hot and can result in hardware damage, it can also cause issues with the power supply if you are sing one that is rated for 60W!


March 23rd, 2014 at 18:20

Miner, thanks man. you hit the nail on the head. I changed hotswap to 5 and added them one at a time with cgminerbtc running. Worked like a charm. Hopefully I dont need to do that after every restart, but it runing 11 seeds in dual mode now.


March 23rd, 2014 at 19:10

That’s great. I do it that way because I only have 3 and they’re not on a hub so I have to plug them in individually anyway. When I get a hub I’ll try starting cgminer then plugging the hub in to see if that works.


March 24th, 2014 at 02:51

I have on two hubs for a total of 20. On restart I have to unplug the hubs, start cgminer then plug the hubs back in. Most of the time the cgminer display will freeze after it adds GDS15 or GDS16, but it seems they all mine as indicated by the led’s and the pool hash rate. cpuminer runs fine. I will try more ram tomorrow, but they are running for now. Thanks again


March 25th, 2014 at 02:20

Here’s the deal, you want reliability? Don’t use Windoze…
I’ve been using custom builds of cgminer/cpuminer on my OpenWRT ALIX board for 10 days.
The only errors I’ve encountered have been with my crappy choice of pool (gnash).

If you feel you must use Windows, maybe try VirtualBox/Ubuntu so you don’t have to deal with virtual coms/drivers.
There are many resources out there for building your own miners with Linux.

I’ve never had good luck with Cygwin or MinGW for Windows builds.
For better results, it may be necessary to use VS and re-work the non M$ compatible code, especially
with serial port applications.


March 25th, 2014 at 03:42

Hi, How come my miners are listed under the USB tab(Universal Serial Port Devices) and not in the Com port tab. I can not change the com port number as there is no option for this under the USB section. Lists them as STM32 virtual com port devce.


March 25th, 2014 at 14:08

TC you change the com port in the bat file. As Will said: “gc3355=STM32″


March 29th, 2014 at 18:31

I just downloaded your dual mining package (3/29/14 – 12:35pm) and Symantec is throwing up a virus warning:
File – minerOC.exe
Risk – Trojan.ADH.2


March 29th, 2014 at 18:59

Ken, it is a common problem, most antivirus software detects and reports many of the miners based on cpuminer, cgminer etc. as possible viruses. If you wish you could just compile the miners from source, but you’d still get the same warnings…

Michael K

April 24th, 2014 at 15:52

I tried downloading the dual package, but it says you need a password to unzip. Am I doing something wrong? I also tried to download the original cgminer 3.8.5 for dual BTC mining from a previous post (http://cryptomining-blog.com/wp-content/files/cgminer-3-8-5-gridseed-windows.zip) but it says this link is no longer valid. My gridseeds are up and running great in Scrypt mode only – looking to run them in both scrypt and BTC mode. Any help is greatly appreciated.


April 24th, 2014 at 15:58

Michael K, try again now, it should be working fine again. Something messed up with the file permissions.


April 25th, 2014 at 17:18

I cannot get it to dual mine i think the guide is missing something. Cpuminer needs one driver i can install that and get it to work. Cgminer needs the winusb driver I can get that to work.

I cannot get both to work since is cpuminer is working cg cannot ditect it but to wrong drivers. If I start with cg cpuminer cannot connect since there is not comport due to the win usb drivers.


April 25th, 2014 at 17:20

Sean, you need to note the COM port number before replacing the driver with Zadig, and after that to set that same COM port to cpuminer and it should work.


July 24th, 2014 at 11:12

I cant get this to work either, my gridseed wont mine BTC for some reason. I can mine LTC by itself but the second I follow your instructions and fire up the BTC miner it appears as if its going to work. However I get 0 shares, all are stale / invalid shares… any ideas?


August 8th, 2014 at 05:16

This particular link contains a trojan virus. Don’t run it.


August 8th, 2014 at 05:46

The trojan doesn’t unpack until you execute the bat file. The definition name is IDP.trojan.A3582C8B.


August 8th, 2014 at 11:47

John, This is a common problem, most antivirus software detects and reports many of the miners based on cpuminer, cgminer etc. as possible viruses. If you wish you could just compile the miners from source yourself, but you’d still get the same warnings.


August 12th, 2014 at 10:46

What is the best way to dual mine on a raspberry pi?


August 20th, 2014 at 08:38

can also be related to having more gridseed launch cgminer selecting only one or take them all?

I work regularly with 1, 3 are connected when I get stuck all ..


March 6th, 2017 at 09:29

hello why can not I get Litecoin using USB Gridseed 8 T litecoin my Asik wrote me Firmware version 0x13011401


July 10th, 2017 at 11:47

where do i find the bat files


August 9th, 2017 at 05:01

“dualmining package ”The download link has been invalid and please administrator update it for me,thank you very much

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