Rationale:

 - Right now:

   - These pages' Markdown will be rendered when browsing our
     repository in the GitLab web interface

   - The .md extension is more common nowadays: GitHub, GitLab, and various
     other major players have settled on it. Let's get used to it.

 - If we decide to migrate our blueprints to GitLab (#18079),
   this will be a necessary first step.

UEFI/32-bit.md

+[[!tag archived]]
+
+This is about [[!tails_ticket 8471]].
+
+[[!toc levels=2]]
+
+Test reports
+============
+
+This is for what we're shipping in Tails 1.5. Please include:
+
+* exact Tails version
+* exact installation method
+* exact hardware brand and model
+* what's happening
+* what was happening with Tails 1.4.1
+
+Misc. notes
+===========
+
+Regarding the success seen with `bootia32.efi`: why would a 32-bit
+GRUB2 EFI boot loader automatically chainload to our syslinux?
+
+Or is it that `bootia32.efi` is actually from another El Torito image,
+that ships syslinux?
+
+Debian's relevant code lives in the debian-cd, grub2 and
+debian-installer Git repositories. Look for `bootia32.efi`.
+
+Maybe also copy to `EFI/BOOT/boot.efi`: grub2's changelog says that
+`grub-install` copies `bootia32.efi` to `boot.efi`, to better support
+old Macs:
+
+ * doesn't work for me on a MacBook Air original 1.8 GHz A1237
+
+Risk of regressions
+-------------------
+
+Here we discuss the risk of regressions, for hardware that previously
+booted Tails just fine, if we shipped a 32-bit UEFI boot loader in our
+hybrid ISO image.
+
+XXX: I (intrigeri) am waiting for answers by an expert in this domain.
+
+What we know so far:
+
+* Early Intel Macs cannot boot from a DVD with more than one El Torito
+  boot record. But we're not considering supporting EFI boot off DVD
+  yet, so for now it's a non-issue. And when we'll have to consider
+  supporting this feature, chances are that most such machines are
+  dead anyway.
+
+Test results and ideas
+----------------------
+
+### 32-bit GRUB2 EFI chainloading 32-bit syslinux EFI
+
+* syslinux 32-bit EFI installed in `EFI/TAILS32`
+* GRUB 32-bit EFI installed in `EFI/BOOT/bootia32.efi`
+
+=> did not manage to chainload 32-bit syslinux EFI from GRUB.
+On Tails/Jessie (GRUB 2.02~beta2-22), I get `error: unknown error.`
+after typing `boot`. This likely comes from
+`grub-core/loader/efi/chainloader.c`.
+
+### 32-bit GRUB2 EFI reading the syslinux configuration at runtime
+
+With current `feature/8471-32-bit-UEFI`, one can choose the *syslinux:
+liveamd64.cfg* menu entry, that basically load syslinux'
+`/efi/boot/liveamd64.cfg`, converting it to GRUB on the fly.
+
+Then, add `nomodeset` if needed, and Tails boots.
+
+Note that:
+
+* Support for `{vesa,}menu.c32` was added in GRUB upstream, but didn't
+  make it into Debian yet as of 2.02~beta2-22.
+  so `feature/8471-32-bit-UEFI` installs a
+  2.02~beta2-22tails1~bpo70+1 package with that new code in it,
+  and indeed it successfully loads our syslinux configuration.
+* We'll need to load the `cpuid` module to make our `ifcpu64`
+  directives work.
+
+### 32-bit GRUB2 EFI with native configuration
+
+If `syslinux_configfile` is not good enough, should not be too hard to
+write/generate and maintain a GRUB2 configuration, either
+automatically (e.g. with `grub-syslinux2cfg`) or by hand.
+
+That's what `feature/8471-32-bit-UEFI` currently does, as a way to
+quickly get things going.
+
+<a id="hardware"></a>
+
+Potential hardware
+==================
+
+Current selection
+-----------------
+
+* in the cheapest range: WinBook TW700
+* with 2GB of RAM: Toshiba Encore 2
+
+Boots GNU/Linux from USB
+------------------------
+
+All of the following tablets are based on the Intel Bay Trail platform
+with 32-bit UEFI firmware and ship with Windows 8.1 except where
+noted. LCD resolutions are generally 1,280x800 pixels, except
+where noted.
+
+They have all been reported to run GNU/Linux from USB with the right
+boot code, but device drivers are sometimes a problem.
+
+There are significant variations in specific firmware features among
+these devices. For example, it's unclear if all of these models can
+cold-boot from USB, or if some may need to start Windows and then use
+the "boot from USB" feature. Most have Secure Boot enabled by default,
+but this feature can usually be disabled.
+
+ * Acer Aspire Switch 10
+   - $300
+   - 2 GB RAM, 10", hybrid
+
+ * Asus T100
+   - $290
+   - 2 GB RAM, 10", hybrid
+   - hardware support on Linux was not entirely awful a year ago, but
+     requires proprietary firmware; not sure where things are at now
+
+ * Asus T100TA
+   - $300
+   - 2 GB RAM, 10", hybrid
+   - 1 USB + 1 micro USB
+   - does the T100's hardware support status apply here too?
+
+ * Dell Venue 8 Pro 3000
+   - $170
+   - 1 GB RAM, 8"
+   - cold-boot from USB: [seems
+     possible](https://www.happyassassin.net/2013/11/24/the-fedlet-revived-or-fedora-linux-on-a-dell-venue-8-pro-bay-trail/)
+     1. Requires a USB OTG converter (full-size USB female port on one end,
+        micro-USB male connector on the other end)
+     2. "press the power button and hold down the 'volume down' key
+        for a couple of seconds (this is how you get into the
+        firmware), go to the Boot tab, disable Secure Boot, and
+        promote the USB stick to #1 in the boot order"
+
+ * Dell Venue 8 Pro 5000
+   - $210
+   - 2 GB RAM, 8"
+   - cold-boot from USB: likely the same as the Dell Venue 8 Pro 3000
+
+ * Dell Venue 8 7000
+   - Ships with Android KitKat; Lollipop due later in 2015
+   - $400
+   - 2 GB RAM/16 GB flash
+   - Notable for high-res 8.4" 2,560x1,600 OLED display
+   - Also includes Intel RealSense multiple-camera subsystem
+   - No cold-boot nor warm-boot from USB, according to png.
+     Perhaps it's possible after [unlocking its
+     bootloader](http://unlock-bootloader.info/mp3-0/dell-venue-8-7000-6714.html)
+
+ * HP Stream 7
+   - $100
+   - 1 GB RAM/16 GB flash, 7"
+   - hardware support on Linux seems not entirely awful, but requires
+     a few out-of-tree drivers:
+     <https://ubuntuforums.org/showthread.php?t=2261294>
+
+ * HP Stream 8
+   - $150
+   - 1 GB RAM, 7"
+   - Includes 4G WWAN modem with limited free T-Mobile Internet service
+   - Believed to be generally similar to the HP Stream 7 otherwise
+   - Can cold-boot from USB:
+     1. Hold down Vol-, press Power for about a second, and release
+        Vol- when the boot options screen comes up.
+     2. That screen gives access to a Boot Device Options menu, BIOS
+        Setup, and other functions including an on-screen keyboard.
+     3. In the Boot Options Menu, one can select Boot from EFI File
+        and push the soft Enter key… and then, with a Tails boot
+        drive, it goes to a File Explorer screen to allow the user to
+        choose between booting from the Tails volume and the NO VOLUME
+        LABEL volume on the USB thumb drive. Sadly, there's no way to
+        press Enter! The Stream 8 has a capacitive Windows button on
+        the bezel, and that just isn’t active at this point.
+        There isn’t a timeout autoselect for the first (presumably
+        correct) option, either.
+     4. This should all work fine by plugging an OTG-Type A adapter
+        cable, a USB hub, a USB thumb drive, and a keyboard.
+        This should be good enough for development, but not for
+        actual users.
+
+ * Lenovo Miix 2
+   - $220
+   - 2 GB RAM
+
+ * Toshiba Encore 2
+   - many models with 1 GB RAM, 8"
+   - WT8-B264 with 2 GB RAM/32 GB flash, 8"
+   - 10" LCD models also available
+   - can cold-boot from USB: hold down the Vol+ button, then hold down
+     the Power button, until the boot selection menu appears.
+     Select the desired boot device and press the Windows key.
+
+* Toshiba Encore 2 Write
+   - Includes Wacom Feel pen/touch digitizer; unusual among low-cost
+     x86 tablets, enables good handwriting recognition and artistic
+     drawing
+   - Otherwise apparently similar to Encore 2
+   - 8-inch version retails for $350
+   - 10.1-inch model priced at $400
+
+ * WinBook TW700:
+   - $60
+   - 1 GB RAM/16GB flash, 7"
+   - To cold-boot from USB:
+     1. Configure the UEFI BIOS to put "USB HD"
+        above the Windows Boot Manager or the internal eMMC storage.
+     2. Plug the USB device in the Type A port, not the Micro
+        USB OTG port.
+     3. Then the tablet will boot from USB without pushing any
+        buttons, and one can still use the OTG port to power the
+        tablet while running from Tails.
+
+Needs more research
+-------------------
+
+ * ASUS VivoTab 8
+   - $190
+   - Bay Trail, 2 GB RAM, 8"
+   - 32-bit UEFI?
+
+
+Boots current Tails and thus uninteresting here
+-----------------------------------------------
+
+ * HP Slate 500
+ * Samsung Series 7 Slate
+ * Microsoft Surface Pro