Geekmaster's adventures in K1 spelunking

[knc1]

Originally Posted by geekmaster

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NOT working on K2 (hangs) or on PW3 (hangs). Well, this is new behavior -- no segfault or "Illegal instruction". Just a good old hung app. On earlier PW3 firmware, this armv4l "hello" program segfaulted as I recall. Same build environment, but fresh compile. New behavior. Never tested on the K2 before now. I expected a segfault on K2 and PW3, but just hanging instead.
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Different OS/ABI
K1 uses "ARM"
Everything since then expects: "UNIX - System V"

= = =

The closest you can come to 'one size fits all' is a single code, two builds.
One to match the OS/ABI of the K1, one to match the OS/ABI of everything else.

(The emulation tools must support both and are auto-selecting the correct emulation.)

So just keep on, keeping on - all conditions normal.

[geekmaster]

So the OS/ABI differences mean system call incompatibilities?

[knc1]

Correct, different register usage.

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We had the answer about a week ago, but didn't notice it.

Recall I mentioned that vintage compiler for ARMv4 didn't have abi choices, because that was when there was only one abi?

Yup - I had the answer a week ago and just didn't notice it.

[NiLuJe]

Yeah, I noticed that the EABI version flag was different, too (4 vs 5), but then promptly forgot about it :/.

[knc1]

I think that would be the OABI compiler directive (IIRC).
It is easy enough to check, build something and see what readelf has to say about.

[geekmaster]

Rob Landley was talking about how ancient and unmaintained a lot of that code was (though mostly the parts of linux that wrap around the uClibc) in his toybox roadmap. The main reason he was using it was for nommu (arms without memory management) support. Most linux distros abandoned nommu support aeons ago. The only reason K1 used it is that lab126 (probably) began software development on E-Ink's E-Paper Display (EPD) dev kit, which was based on the Apollo eink controller and gumstix board with uClibc. Apparently they learned enough from the three years spent bringing that to market to switch to a freescale SoC and epson Broadsheet eink controller and glibc for the K2.

Regarding musl builds for the K1, the toybox roadmap says this:

Note: toybox can autodetect nommu support when building with a uClibc toolchain such as the one from Aboriginal Linux, but with musl-libc you'll have to enable CONFIG_TOYBOX_MUSL_NOMMU_IS_BROKEN to work around the fact they provide a non-functional fork() implementation that always returns -ENOSYS, to prevent you from compile-time probing for nommu support when cross-compiling. Unfortunately "preventing you from probing" seems to be an explicit policy with musl, they also don't provide an "#ifdef __MUSL__" because their library is perfect and you're only ever allowed to work around other people's bugs, not theirs. So we have to use menuconfig to manually enable musl-specific bug workarounds.

And regarding K2s, I just received a K2 that was bulged on the front and the back, with the side seam split open. On opening, its battery is swelled to literally THREE times its original thickness. Thankfully, the battery was mounted behind the keyboard and not the fragile eink display. I will take photos, and investigate replacing the internal LiPo inside the plastic battery frame with a cheap-ass replacement from a cheap-ass remote control toy (keeping the little circuit board that identifies it as a genuine amazon battery).

P.S. I have KUAL and usbnet running fine on another K2, along with my Video Player KUAL extension. Though I did not yet add a "press a key to abort early" to the extension, unlike my K1 where I do not have to sit and wait for "Big Buck Bunny" to play to completion (or abort it from an SSH shell). I also have this video player extension on my PW3 (where the 800x600 video only occupies about a quarter of the display).

[geekmaster]

There are claims that glibc cannot be built on an EABI armv4 system:
https://sourceware.org/bugzilla/show_bug.cgi?id=12097

But there was an interesting comment posted at that link above:

Ignore my previous note.

-march=armv5 -mtune=xscale

produces bad binaries for xscale.

./hello
Illegal instruction

building with -mcpu=xscale (no -march or -mtune) does not need this patch.

Perhaps uClibc is the only option for working toolchains for the K1? And for some reason Rob Landly kept aboriginal armv4l using uClibc even after converting all else to musl. I have not stumbled upon his rationale for that build choice yet though... But that comment in the link above makes me wonder.

I am also curious if one of the OLD versions of aboriginal armv4l might have the right version of GCC for building K1-compatible kernel modules. If not, I will need to succeed at building the toolchain from the source included with the K1 GPL source code from amazon (if in fact that is even the right GCC version for building K1 FW 1.2 kernel modules).

I do like this comment in one of Rob Landley's README files:

If you don't do cross compiling already, this project isn't going to teach you how, and in fact recommends you just don't go there. We cross compile so you don't have to.

[knc1]

Disclaimer:
I haven't used Aboriginal for several years.

There should be a place to replace the download url(s) with a file:/// uri (to copy **your** version from a directory on the file system).

[NiLuJe]

@GM: Switching from march + mtune to mcpu was my second attempt. But, then again, that was still on EABI5, so, ;D.

But yeah, on ARM, configuring GCC with --with-cpu= is recommended over the arch/tune combo.

[geekmaster]

I just received another K1. This one is in its orignal (book shaped) box, with all original accessories (including the paper manual), and a leather cover. The only thing NOT new about it is that it is still registered, and full of ebooks. After I make a backup copy, I will return all the ebooks to the registered account so the licenses can be reused by the original owner, then I will deregister it (as before with other kindles).

[geekmaster]

My first K1 is running firmware 1.0.8. My second K1 came with FW 1.2 (the latest). This recent arrival has FW 1.1.1 on it.

[geekmaster]

Perhaps unwise, considering all the unfinished projects I want to complete in my next six lifetimes, but I am seriously considering writing an ARM assembler HAL shim (for "educational" purposes), to wedge in whichever ABI method is needed for the current environment, so my kindle proggies can be ABI-proof and run on "all the kindles". Yeah, not a profitable activity, considering that I need to find a reliable source of income (or a reliable sponsor/benefactor, unlike my previous sponsor) at this phase of my life (no longer savings-supported). A lot simpler to just use a startup script that launches whichever program will work (perhaps based on the K1 or "not K1" serial number prefix).

Perhaps writing apps for my GearVR or my Oculus Rift (all-new Consumer Version) that I could sell in the app stores would be a better use of my time. By my muse had pushed me back into these forums again, with a recent fascination with my K1(s)...

I wonder if patreon can work for me. I can live rather inexpensively at my current location, though moving to a costly location (i.e. not in "flyover country") would change that...

I have never really distinguished between work and hobby -- I love getting paid to do what I love to do, and such as been the bulk of my career. I just need my "hobbies" to be profitable again.

Advice and suggestions are more than welcome, on where I should go from here.

[geekmaster]

One thing of potential interest in decoding kindle serial numbers, is that the K1 (like the K2) has its REAL serial number printed on the back. Unlike the K2 and later which group their serial number into a long string of characters, the K1 groups the serial number into small batches of characters with spaces between them:

B0 01abcd efgh ijkl (or B1 01abcd efgh ijkl).

Probably not that useful, but another factoidal tidbit from the K1 "spelunking adventures".

[geekmaster]

Okay, my latest K1 acquisition has been backed up. Radio on, and even without the new cert update it still adjusted the time to NOW (though it took a couple of minutes to do so).

Interestingly (like my recent PW2 acquisition), it is still registered, so the previous owner apparently did not deregister it from their amazon account login. Meh, I was mistaken. It needs the cert update to connect to the amazon account ("cannot connect at this time")...

So rather than keep the old firmware version, I need to upgrade just so I can return all those book licenses to their original owner (the "right" thing to do)...

[geekmaster]

Just for a test, I copied the 1.2.1 update (which is just a cert file and a little script to install that cert) without upgrading from 1.1.1 to 1.2 first. UYK was grayed out. Then during the upgrade to 1.2 I noticed something interesting -- unlike the "update_install" process (when running my scripts), this 1.2 update draws a pair of little icons at the bottom of the screen when it first begins the update -- icons showing battery charge and radio signal strength. But they disappear once "installing" begins.

The next step (firmware flashing, now in progress, is slow) will be to install the cert (1.2.1) update, then return all the books to the previous owner, then deregister.

Ah... it rebooted, and then displayed "Firmware Update" at the bottom of the screen for awhile. But now changed to "Starting the update...".

I am curious to see if the previous owner deregistered this kindle at their end (in their amazon account). If so it should deregister automatically after applying the cert update (the radio is ON -- no risk if a K1 only accepts UNSIGNED update.bin files).

Rebooting now... Ooh... it says "creating base system... initializing... done..."... Rebooting -- did it eat all the books before they coud be returned to increment the license counts? -- Reboot complete. Still "Michele's Kindle" and still full of books. I wonder what that "initializing" was all about.

Still "cannot connect at this time". New cert still needed. The cert update also shows the battery and radio icons at the bottom of the screen. My update.bin files (that run "Big Buck Bunny" and stuff) do not show those icons on the other kindles (FW 1.0.8 and 1.2).

Cert applied, still registered (even with radio on). Hmm, on a K1, I see no option to return books, only to delete them. On the PW2, of the 135 books on it, most could be returned, and only a few only allow "delete". I wonder if there is any benefit to deleting books -- will their license counts be adjusted a the owner's amazon account? I am suspicious because going to the Kindle store says "welcome, guest" even though this K1 says it is registered.

I think maybe the previous owner may have deleted their amazon account... Though I already backed up this K1, so deleting those books will at least free up some space. I have more ebooks in my collection than I can read in a lifetime already...

My concern is that unlike returning a book, deleting it might also delete it from the registered account -- not sure how that works.

I decided to do a factory reset. That should be safe for the device and the previous owner's account. Hmm... no factory reset in the menus. I must delete all the books one by one? Or write an install script to whack the partition?

Ahh, the "content manger" lets me process whole pages of book titles, at least. I can "remove" them, or move them between SD card and "kindle memory". Except that "remove" option DOES NOT WORK (at least not when all items on a page are selected). They are still there after multiple "remove all" attempts. Except now I can no longer "Select All", so maybe they ARE gone? I see a "Refrehs Lis of Items" option. Nope! Still there, but I can no longer "Select All". Though after sorting them, I can "Select All Items on Page" again. But after selecting. "Remove Selected Items" is greyed out this time, and it oly lets me "Deselect" or "Move to Kindle Memory" (which is funky considering there is no SD card installed) -- or do they mean "Move from the amazon account", in which case "deleting" them really DID return them to the original owner?

I wonder why there is no obvious way to do a factory reset...

EDIT: After returning to the HOME page several times, now it suddenly has only four books on it, so apparently the deletes just took a few minutes... I just went to the content manager to delete those four books, and ALL the books (both pages) show up there. So it must be showing me books on the amazon account too -- so they WERE returned, it seems. Except those four books. ... Okay, now all items returned. Nothing on Home menu. But content manager still shows all books with option to "Move to Kindle", so they must be only in the previous owner's amazon account now. TIme to deregister... Okay, deregistered warned I may want to transfer subscriptions with the account manager -- done. No device name or owner on this K1 now. All books returned to original purchaser. All is well...