iLiad Where is zImage in iLiad?

ericshliao · 11-12-2008, 12:56 AM

I tried to figure out how does iLiad boot. Generally, a Linux system should have a vmlinuz or zImage in filesystem. On iLiad, I only found a zImage link file in /boot, which links to another non-existed file.

Does iLiad has a mystic storage for zImage and initrd?

In reflash image file realeased by iRex, there are three file: zImage, initrd, and app. What is the format of "app.image"?

-Thomas- · 11-12-2008, 02:42 AM

Quote:

Originally Posted by ericshliao

In reflash image file realeased by iRex, there are three file: zImage, initrd, and app. What is the format of "app.image"?

app.image is a disk image for the root file system, created like this:

Code:

dd if=/dev/tffsaX of=app.image

There is a similar thread over here.

ericshliao · 11-12-2008, 04:20 AM

Quote:

Originally Posted by -Thomas-

There is a similar thread over here.

Thanx. That's a rather old thread. I would never find it if not being told.

Adam B. · 11-12-2008, 05:55 AM

App.image is an ext2 file system image. You can mount it on any linux computer with a "mount -o loop". This is how we will make custom firmware versions.

zimage and initrd are flashed to a non user accessable file system with the reflash procedure. The iLiad actually contains 2, the normal one that is used to boot, and the second which is used for recovery and is called when holding the IDS button on boot.

ericshliao · 11-12-2008, 02:49 PM

Thanx for your instruction.
I am thinking about backup my iLiad to a reflashable image, so that I don't have to connect to iDS to get update after reflash.
To do it, I have to build kernel, initrd, and app image. By conjecture, the kernel is not changed in FW2.10, 2.11, 2.12, so it's ready. To build initrd, I have to use mkinitrd on iLiad. But I haven't found a source code package for cross-compiling.

Adam B. · 11-12-2008, 02:56 PM

Did you change your initrd? What are you trying to back up? Are you simply wanting to reflash with the latest 2.12 firmware image?

ericshliao · 11-12-2008, 03:05 PM

I just want to reflash to FW2.12. Besides, I have installed some files in iLiad, I want to backup them, too. I compared two initrd in reflash rom images released by iRex, and found that they are different, so I guess that it is changed in FW2.12. That means, I can't use initrd in reflash rom image to reflash FW2.12.

Adam B. · 11-12-2008, 03:15 PM

There are 2 initrd images, the original that is used when booting, and the other that's used for reflashing. I don't believe the initrd has changed in 2.12. I've reflashed with the 2.12 app.image without a problem.

ericshliao · 11-12-2008, 03:45 PM

I have two version of reflash rom image downloaded from iRex in different time. One is older, one is newer. I compared the two initrd files in them and found that they are different.
Since you confirmed that initrd is not changed in FW2.12, I guess you mean the newer version reflash rom image use the same initrd as FW2.12.
Then it will make things go easier. I only need to prepare my own app image and adopt zimage and initrd in reflash rom image to build my own private reflash rom image.

-Thomas- · 11-13-2008, 12:23 PM

Backing up your whole iLiad is a great idea. I was always kind of hesitant when I wanted to do some major hacking, because I didn't want to go back to 2.10 if anything went wrong. But this would really help me alot.

IIRC there was a way to boot a custom kernel/initrd via the reflashing mechanism. Maybe we could use a custom initrd including a backup script which will backup your flash partitions to CF once you boot it?

jharker · 11-14-2008, 11:21 AM

What I'm particularly interested in are these questions:

Where exactly are the zImage and initrd files located on the iLiad?
Is there any way to access / change / read them?
How do we provide new zImage & initrd files to replace the old ones when we upgrade the system?
What about the super-secret only-in-case-of-emergencies kernel? Where is that kept, and how might it be accessed?

I threw in question #4 because I'm interested in that part of the boot process that happens before init is called -- that is, the intra-kernel boot time and how long it takes.

But for starters, the answers to questions #1-#3 would be very useful.

Adam B. · 11-14-2008, 11:50 AM

Quote:

Originally Posted by jharker

What I'm particularly interested in are these questions:

Where exactly are the zImage and initrd files located on the iLiad?
Is there any way to access / change / read them?
How do we provide new zImage & initrd files to replace the old ones when we upgrade the system?
What about the super-secret only-in-case-of-emergencies kernel? Where is that kept, and how might it be accessed?

I threw in question #4 because I'm interested in that part of the boot process that happens before init is called -- that is, the intra-kernel boot time and how long it takes.

But for starters, the answers to questions #1-#3 would be very useful.

I don't think knowing their physical location is all that important. But I'm sure we can figure it out.

We can modify and reflash them. See the instructions in this pdf for details on how to do that.

The linuxrc boot script from the current initrd is attached. It should provide some insight on how the iLiad boots.

Adam B. · 11-14-2008, 12:00 PM

And here's the linuxrc that's called when you hold down the IDS button on boot.

There is a way to replace this one, but I don't think we should touch it.... if something goes wrong, people loose the ability to reflash their iLiad.

jharker · 11-14-2008, 12:19 PM

Ooh. Adam, you rock.

Some comments occurred to me, but they're actually more relevant to the redistribution thread, so I added a comment over there.

gingercat · 06-12-2010, 01:08 AM

so did anyone ever get a working 2.12 image that would run off the CF card?

11-12-2008, 03:45 PM	#9
ericshliao Guru Posts: 976 Karma: 687 Join Date: Nov 2007 Device: Dell X51v; iLiad v2	I have two version of reflash rom image downloaded from iRex in different time. One is older, one is newer. I compared the two initrd files in them and found that they are different. Since you confirmed that initrd is not changed in FW2.12, I guess you mean the newer version reflash rom image use the same initrd as FW2.12. Then it will make things go easier. I only need to prepare my own app image and adopt zimage and initrd in reflash rom image to build my own private reflash rom image. Last edited by ericshliao; 11-12-2008 at 03:53 PM.

11-14-2008, 11:21 AM	#11
jharker Developer Posts: 345 Karma: 3473 Join Date: Apr 2007 Location: Brooklyn, NY, USA Device: iRex iLiad v1, Blackberry Tour, Kindle DX, iPad.	What I'm particularly interested in are these questions: Where exactly are the zImage and initrd files located on the iLiad? Is there any way to access / change / read them? How do we provide new zImage & initrd files to replace the old ones when we upgrade the system? What about the super-secret only-in-case-of-emergencies kernel? Where is that kept, and how might it be accessed? I threw in question #4 because I'm interested in that part of the boot process that happens before init is called -- that is, the intra-kernel boot time and how long it takes. But for starters, the answers to questions #1-#3 would be very useful.

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11-12-2008, 12:56 AM	#1
ericshliao Guru Posts: 976 Karma: 687 Join Date: Nov 2007 Device: Dell X51v; iLiad v2	Where is zImage in iLiad? I tried to figure out how does iLiad boot. Generally, a Linux system should have a vmlinuz or zImage in filesystem. On iLiad, I only found a zImage link file in /boot, which links to another non-existed file. Does iLiad has a mystic storage for zImage and initrd? In reflash image file realeased by iRex, there are three file: zImage, initrd, and app. What is the format of "app.image"?

11-12-2008, 05:55 AM	#4
Adam B. Addicted to Porting Posts: 1,697 Karma: 7194 Join Date: Oct 2006 Location: Indianapolis, IN Device: iRex iLiad, Nokia 770, Samsung i760	App.image is an ext2 file system image. You can mount it on any linux computer with a "mount -o loop". This is how we will make custom firmware versions. zimage and initrd are flashed to a non user accessable file system with the reflash procedure. The iLiad actually contains 2, the normal one that is used to boot, and the second which is used for recovery and is called when holding the IDS button on boot.

11-12-2008, 02:49 PM	#5
ericshliao Guru Posts: 976 Karma: 687 Join Date: Nov 2007 Device: Dell X51v; iLiad v2	Thanx for your instruction. I am thinking about backup my iLiad to a reflashable image, so that I don't have to connect to iDS to get update after reflash. To do it, I have to build kernel, initrd, and app image. By conjecture, the kernel is not changed in FW2.10, 2.11, 2.12, so it's ready. To build initrd, I have to use mkinitrd on iLiad. But I haven't found a source code package for cross-compiling.

11-12-2008, 02:56 PM	#6
Adam B. Addicted to Porting Posts: 1,697 Karma: 7194 Join Date: Oct 2006 Location: Indianapolis, IN Device: iRex iLiad, Nokia 770, Samsung i760	Did you change your initrd? What are you trying to back up? Are you simply wanting to reflash with the latest 2.12 firmware image?

11-12-2008, 03:05 PM	#7
ericshliao Guru Posts: 976 Karma: 687 Join Date: Nov 2007 Device: Dell X51v; iLiad v2	I just want to reflash to FW2.12. Besides, I have installed some files in iLiad, I want to backup them, too. I compared two initrd in reflash rom images released by iRex, and found that they are different, so I guess that it is changed in FW2.12. That means, I can't use initrd in reflash rom image to reflash FW2.12.

11-12-2008, 03:15 PM	#8
Adam B. Addicted to Porting Posts: 1,697 Karma: 7194 Join Date: Oct 2006 Location: Indianapolis, IN Device: iRex iLiad, Nokia 770, Samsung i760	There are 2 initrd images, the original that is used when booting, and the other that's used for reflashing. I don't believe the initrd has changed in 2.12. I've reflashed with the 2.12 app.image without a problem.

11-13-2008, 12:23 PM	#10
-Thomas- Addict Posts: 325 Karma: 1725 Join Date: Dec 2007 Location: Münster, Germany Device: iRex iLiad v2	Backing up your whole iLiad is a great idea. I was always kind of hesitant when I wanted to do some major hacking, because I didn't want to go back to 2.10 if anything went wrong. But this would really help me alot. IIRC there was a way to boot a custom kernel/initrd via the reflashing mechanism. Maybe we could use a custom initrd including a backup script which will backup your flash partitions to CF once you boot it?

11-14-2008, 12:19 PM	#14
jharker Developer Posts: 345 Karma: 3473 Join Date: Apr 2007 Location: Brooklyn, NY, USA Device: iRex iLiad v1, Blackberry Tour, Kindle DX, iPad.	Ooh. Adam, you rock. Some comments occurred to me, but they're actually more relevant to the redistribution thread, so I added a comment over there.

06-12-2010, 01:08 AM	#15
gingercat Connoisseur Posts: 92 Karma: 10 Join Date: Jul 2007 Device: iRex iliad	so did anyone ever get a working 2.12 image that would run off the CF card?

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