Oh sorry, I misunderstood the question. There are some instructions in English here on the MR site where you can do a swap of the system fonts. (There are I believe three system fonts each used for different situations.) I chose not to go that route so as to be able to choose from any font I installed, but some have done the swapping. I have no idea if either method works with porkupan's (boroda) modified firmware, but my guess is that they do.

Also, the method I documented, but many others developed, was originally for the older Sony Readers (300, 600, and 900). But I've used it on both my 350 and 950 with great success. I think the other method will probably work on the newer models too.

I wish I had a link for you to the other method discussion, but I don't. You can do a search though.

Once again, I want to stress that my document is merely a compulation of the method developed by others and contained in a VERY long thread on this forum. I find threads difficult to follow when they have 10s of pages and so I took all the info, compiled it, tested it, refined it a bit, and wrote it into something I could understand and do. I was a technical writer for 25 years so that comes natural to me.