Notices

I was looking at about:config with the filter useragent and found the variable general.useragent.vendor which has a string of Firefox/3.5 Maemo Browser 1.7.4.8 RX-51 N900.

Tried to change it to something else but community.letsencrypt.org still complains about an old browser.

Also the new string inserted doesn't seem to be saved after a browser restart (I find the old string instead).

Could community.letsencrypt.org be using this variable to identify the device?

For anything where security matters, you shouldn't use any browser from the Debian repository, except for Firefox (formerly Iceweasel) and Chromium.
The reason is, that all other browsers run a webkit engine of some sort, which under Linux is simply in a constantly terrible state when it comes to security. [1]

I guess interacting with letsencrypt.org qualifies as security-critical, because if you can't even ensure the security on your end of the line, then using their service makes no sense in the first place.
Since Chromium isn't available for arm, Firefox is your only choice on the N900. But even that should be taken with a grain of salt because I don't know what I might have silently broken by accident, when allowing Easy Debian's glibc to be compiled against Maemo's kernel 2.6.28. And even assuming I didn't break anything (I don't say I didn't!), there's still the question if Memo's kernel is still up to handling current security issues. I'm not qualified to judge that. Maybe pali or fremangordon are.

bottom line:
For me there are just too many open questions to trust Maemo's/Easy Debian's/any browser's security chain when it really matters.


[1] https://www.debian.org/releases/stab...owser-security

Iceweasel / Firefox is currently too bloated for Easy Debian to be really functional. It is very unresponsive (with often script errors). I managed to get something done, but waiting for page build up is painfully slow and crashes occur.

Anyone that uses a N900 in 2016 should know there is a (small?) security risk involved .
CSSU is great, but the group of people working on it is pretty small. Somewhere on this forum there is a thread with to-do list with a lot of the current vulnerabilities of Fremantle.

At least Surf works for all sites I throw at it and is still maintained (actively) today, that is more than you can say from the stock M5 browser.
Malakai wants to use the stock browser to visit letsencrypt.org

So, I had time to install Easy Debian with a Debian Jessie image.
Sadly Iceweasel is way too slow to be usable.

Will try Surf another time to see.

and Midori

For desperate cases I use uzbl, with a small modification for 'touch' scrolling. Very slow anyway, unfortunately, but definitively more uzbl than Iceweasel

So, after dealing with some issues on Easy Debian Jessie image (thanks sulu for the help), I installed surf and midori.
Both are faster than Iceweasel but the user experience is far from the one with the built in Maemo browser. Scrolling is kind of a pain and none of the 2 browsers are made for gesture control (because they were not intended to be used on a touchscreen).
So my usage of surf or midori will be, as jurop88 said, for desperate cases when I really need to check the websites that don't work on Maemo's built in browser and it can't wait for me to get to a computer (which means almost never).

Anyway thanks for all your contribution in solving this.