@yuyquan 

Frist make sure the HS105 has had its set up completed, meaning its paired onto your network.  Next make sure the router has given it an IP address by logging into your router and checking its client list.  Its quite possible your router may not be giving the device an IP address and this is why the firmware update is not working.  If it iyou cs in the client list and you can control locally then you should be able to update the firmware.  If its failing after confriming these two steps then you may need a replacement device.  Which our support team would be happy to help with, as long as your device is still in the 2-year warranty.  

As for your second item,  Google home can only see the device is remote control is enabled.  Once that issue is resolved google should see the device and be able to control it

Best Regards

Carl | TP-Link Support 

My hs105 has this same issue.  The message I get is “cloud send cmd failed” when I try to enable remote access.  The firmware upgrade looks like it completes successfully but it keeps displaying the previous version 1.4 after completion.  Please send me a replacement. 

@Joesssss 

replacements can not be handled at this time through Forums.  You would need to contact our support line 866-225-8139 or through email @ Kasa.Support@tp-link.com.  Support will need details of the issue and your setup and also what troubleshooting steps you have followed.  We will also need to check eligibility by obtaining your proof of purchase.  Once that has been established and completed Support will apporve a replacement if you are in warranty

Best Regards

Carl | TP-Link Support 

@yuyquan This worked for me after downloading the software and changing my pc connection to 2.4 ghz.  Took three times of running the update process before it finally did.  But it only took me to the 1.5.1 firmware version.  The latest as of now is 1.5.6.  Still can't update on the Kasa app.  Keeps failing.

https://community.tp-link.com/us/home/forum/topic/103538