Ended up ditching speeding up serial connection ideas and went for hardware solution - sdwire (+ plugin) - SDWire - Tizen Wiki .
I know this thread is a bit old now, though thought I would ask anyway. Are you still using your SDwire and is it good. I have been to the Tizen web site, and they are out of stock, does anyone know when they will be back in stock (I have signed up to email list).
I have only had my printer for about 6 months, so missed the initial SDwire sale. If anyone knows where I could get one, or if there are any other similar available products. Please let me know.
You could probably get a fiber-punk node device, I have one and it works fairly well for SD card switching. I need to do some more testing but I created a plugin that will allow you to upload to it when uploading to SD card.
Still using sdwire and I'm very happy with it. They have it in stock now (bought one more recently).
But with 32bit prusa hardware (MK4, MK3.5, mini) there is no sd card anymore and only usb stick, so at some future point sdwire will not help.
No. 32bit, called "xBuddy"
Also it turns out there is a solution for boards using usb storage (instead of sd card):
https://www.kernel.org/doc/Documentation/usb/mass-storage.txt
https://linux-sunxi.org/USB_Gadget/Mass_storage
It doesn't require any additional hardware (beside raspberry pi only for example). No octoprint plugin for it so far.
Opps, my wrong. Time is passing by too fast...
Mixed MK3.5 up with the MK3S