Q:

How to deal with (in my opinion) bad firmware design forced by my boss

First some back-story. 
We (4 Developers, 1 of them is my Boss) are currently in the process of designing a new iteration of one of our products.  So my boss told me to come up with a new firmware-update mechanism for this specific product.  I sat together with our technicians (those who do the firmware-updates in the field, and have to deal with our customers) on how the new update-process should work. 
We came up with an clever dual-firmware-image solution which does backups of itself when updating so in case if something goes wrong, we always have a working (backup) image and the device is still usable (i.e. it can still run without manual intervention which is  very important in terms of availability which is also very important for this product). 
I presented this approach to my boss and he absolutely dislikes it.  He wants an "Firmware-Image+Recovery-Image" solution. 
His main reason is that thus we don't waste space to keep a mirrored image on the device. 
I already told him about the disadvantages like maintaining two images, we have to implement a lot of new stuff in our well tested bootloader and DTS which again requires extensive testing, thus I have to waste a lot of time just implementing this instead of using already well implemented methods, and of course the biggest drawback: the usability.  Every time an update fails (i.e. customer pulls the plug while updating) we only have a recovery image where the user/technician has to manually fix things.  This produces a lot of work for our technicians and may upset customers since the device is not working until someone manually fixes it (99% of the time our technicians), remember: availability is key to this product. 
My Problem: 
Ok, my boss wants it like this, he can have it.  This is not my part of business.  However, I have a really hard time to implement something that does not feel good to me.  Every line of code I write feels bad and I know this is going to be a huge pain in the ass for our technicians.  My motivation to work on this project already died completely because its just plain bad.  
I know this is very opinion-based, but how do you deal with a situation like that.  How should I proceed on this project?  Most of the time when I tell my boss he has made a poor design decision we discus a lot about it and we find a solution satisfactory for all of us, but this time he insists on this pattern. 

A:

this time he insists on this pattern

Then give him what he wants.  He usually finds a solution satisfactory to everyone but this time is different for whatever reason.  There must be a reasonable explanation on why your boss has done this. 
So complete the task the way he wants and do your job as it should be done.  You're not always going to agree on things you do but it's your job to do it the way that's wanted. 

A:

Do the work you are told, but make sure your plan of attack and its complete disregard is documented.  When you are inevitably questioned for a dumb design later due to internal and external user rage you can use it to protect yourself since it was clearly not your idea. 
You can do this by getting your boss to explicitly state what he wants over what you suggested in writing, through e-mail or whatever. 

Hello, Boss
Could you write a description of the solution you asked us to implement on project? 
We need this requirement description to replace the previous solution we in development had come up with earlier on our tracker. 

Do not argue about which could be better, stick to doing work.  Merely documenting whose idea was it is enough.  Besides, your solution might have a caveat your boss has spotted, who knows?  Neither exist yet.