Font, ScreenSaver & USBNetwork Hacks for Kindle 2.x, 3.x & 4.x

[yifanlu]

Originally Posted by NiLuJe

Update time!

* JailBreak v0.5.N:
* Works on FW 3.1, thanks to yifanlu . But there is a twist. Like I said on the jb thread, it's based on a whitelist of hacks to decide when to switch to our custom key (in order to successfully install a custom hack). You'll find this whitelist in linkjail/etc/whitelist. Right now, I think it covers a whole bunch of hacks, but if for some reason it's missing something (in which case your hack install will fail with a U007 error), here's how to procede:

* Notify me, so I can fix it for everyone .
* Edit the whitelist manually in linkjail/etc/whitelist (the format should be pretty self-explanatory, just make sure it stays with UNIX line endings).
* Alternatively, you can also drop a blank ENABLE_HACK_UPDATES file in the root of your Kindle, like with yifanlu's jailbreak. (As a side-effect, this will make official updates *fail*).

* Fonts V4.3.N:
* Updated FreeType libs (There might be some significant speed/rendering improvements).
* Updated fc-scan binary (fontconfig update)
* Slightly smarter official update 'traps' (it's using the jailbreak whitelist).

* ScreenSavers v0.19.N:
* Updated sort binary (updated coreutils)
* Slightly smarter official update 'traps' (it's using the jailbreak whitelist).

* USBNetwork v0.31.N:
* Updated sftp-server binary (OpenSSH update)
* Updated dropbear binary (dropbear update)
* Updated htop binary (htop update)
* Updated busybox binary (busybox update)
* Updated rsync binary (rsync update)

Nice update. I do not understand the "whitelist" thing though. Let's say I want to install a hack that's on the whitelist. When I copy it to the Kindle, what's letting it know to change keys? I don't see an loop in the linkjail script, or a callback script. If you have to restart for the keychange to take place, why is there a need for a whitelist? Just call otaup's sigcheck function, if it fails, change keys. If you don't need to restart for keychange to take place, can you tell me what's happening?

[NiLuJe]

@yifanlu: linkjail is ran @rc3, before otaup, at which point we can safely compare the *.bin file against the whitelist, and switch keys if needed via a bind mount. It'll be unmounted @rc5 once the update is finished and the framework restarts.

Basically, we have an open window between the 'Update Your Kindle' click and otaup, and the switch is made during that window. We switch back to default keys when the framework restarts (or when the Kindle reboots, since it's a bind mount).

[Hollow Man]

Originally Posted by NiLuJe

If the update process of the uninstall was successful, then everything should be okay.

Thanks. For the heck of it I uninstalled my previous 3.1 jailbreak and tried yours, and all seems good. Thanks again to both you and yifanlu for all the hard work,

-HM

[yifanlu]

Originally Posted by NiLuJe

@yifanlu: linkjail is ran @rc3, before otaup, at which point we can safely compare the *.bin file against the whitelist, and switch keys if needed via a bind mount. It'll be unmounted @rc5 once the update is finished and the framework restarts.

Basically, we have an open window between the 'Update Your Kindle' click and otaup, and the switch is made during that window. We switch back to default keys when the framework restarts (or when the Kindle reboots, since it's a bind mount).

Really? I did not know that. So the Kindle changes boot levels when updating?
What is the rc level at boot? I always though it was rc3. So the Kindle starts at rcsomething, then when you click update, it switches to rc3, and when it's done it's rc5?

So to be clear: Kindle update goes to rc3. Change keys if needed at rc3. Kindle does update & calls rc5. Change keys back at rc5. This way, if a user wants amazon update or hacks, they can just put the update file and it will work (no restart before updating needed?) just like old jailbreaks?

[NiLuJe]

@yifanlu:

Yep, that's it .

Here's the runlevel breakdown on a K3:

rcS is the low level boot runlevel
rc0 is the shutdown runlevel
rc1 is the single user runlevel (probably useless/broken on a Kindle)
rc2 is the diagnostic runlevel
rc3 is the updater runlevel
rc4 is the reboot diagnostic runlevel
rc5 is the boot (framework) runlevel
rc6 is the reboot runlevel

So, yeah, we're usually on rc5, the update process switches to rc3, and goes back to rc5 once it's done (and when the update script doesn't trigger a reboot, like official updates with kernel updates, in which case it just goes from rc3 to reboot. The 3.x updates are even weirder, they drop a temporary init script early during rc5 that'll call otaup from there, and reboot [ie. that's why there's been a shitload of reboots needed for every 3.x official updates]).

[AoifeUnudottir]

Hi everyone,

Sorry if this has been discussed before (I tried to go through the pages to check, but there's 100+!) but has anyone notied reduced battery life with the screensaver hack? My thinking is that if I have too many screensavers, the Kindle has to work too hard to randomise them and so battery life is reduced (however, I also thought that every time the Kindle reboots completely, the random order for screensavers is set once and then followed until the next full reboot).

I have roughly 70 screensavers - is this too many? I got a little carried away...

[If anyone is interested, my first 63 backgrounds are viewable here: http://dark-angel-13.deviantart.com/...vers-198495691 . Once I get permission from the original artists, I'll probably make them available for download]

Thanks for any help you can give me!

[NiLuJe]

@AoifeUnudottir: Nope, it'll only churn for a few seconds more at *boot*, so there's virtually no impact.

[kranu]

Originally Posted by NiLuJe

@kranu:

/etc/uks/pubhackkey01.pem

Then what is pubprodkey01.pem? It's located in the same directory, and as far as I can tell, it's the same as pubhackkey01.pem.

I have 3.1, but it's not jailbroken yet. I just wanted to uninstall the original jailbreak before I install the new one.

[yifanlu]

Thanks for teaching me about the kindle runlevels. I have updated my jailbreak to use this method. However, I also went another step and removed a need for whitelists. My script reads the signature for the update before amazon's updater does and changes keys accordantly.

Also, I don't know if this is just on my kindle but running:
grep "^fsp /etc/uks/pubprodkey01.pem" /proc/mounts
doesn't return anything. On my kindle it's listed as
"/dev/root /etc/uks/pubprodkey01.pem ext3 rw,noatime,nodiratime,data=ordered 0 0" so I'm using:
grep "/etc/uks/pubprodkey01.pem" /proc/mounts
to check.

[NiLuJe]

@kranu: That's amazon's default pubkey. It obviously *souldn't* be the same as our custom pubkey on a vanilla Kindle. (Note that the latest version *still* includes the custom one there since it can be moderately useful for FW 3.0.x users).

@yifanlu: Nice! You're mounting from the ext3 / dir, and I'm mounting from the crazy fuse over loop over fat32 userstore, that explains the inconsistency in our proc/mounts outputs .

[NiLuJe]

Meh. Bump JailBreak to v0.6.N, with a slightly less braindead *uninstall* process (it wasn't switching back to default keys immediately, you'd have to reboot).

[Hollow Man]

Originally Posted by NiLuJe

Meh. Bump JailBreak to v0.6.N, with a slightly less braindead *uninstall* process (it wasn't switching back to default keys immediately, you'd have to reboot).

I assume we can install .6.N right over .5.N, without any uninstalling, correct? Thanks!

-HM

[Sir Alex]

@NiLuJe: Could you please add this hacks to whitelist:
update_loc_ru
update_loc_cz
update_loc_cz2
update_loc_pl
update_loc_ukr
update_loc_bg
update_backup
update_reginfo

[NiLuJe]

@Hollow Man: Only the uninstall script has been changed, you don't need to update anything .

@Sir Alex: Will do, thanks .

[Hollow Man]

Originally Posted by NiLuJe

@Hollow Man: Only the uninstall script has been changed, you don't need to update anything .

I thought this might be the case based on your previous comments, heh, but thought I'd inquire anyway. I'll just download the newest version and tuck it away in case I need to uninstall. Thanks!

-HM