Upgrading NOR Flash on a Vizio XWR100 router.

**stj** · 08-06-2017, 09:02 PM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

you must have the same sector size & layout or the o.s. may not know how to write to it.
other than that, it may work.

you would have to copy the rom data over,
then after you boot it up, you need a serial console to try to change the size of the last partition, or create a new one.
i have no idea if it can be done - you need to investigate the options in your boot code.

**goontron** · 08-06-2017, 09:04 PM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

^ As STJ said, OS dependant. If its some Linux based OS, you'll be fine, if its VxWorks, expect breakage!

**Spork Schivago** · 08-06-2017, 11:58 PM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

I believe it's a Linux based OS. The OpenWRT wiki page I found links to the GPL source code on Vizio's website for it. I'm compiling OpenWRT for it now, even though technically, it's not supported.

The idea was to first remove the current flash, dump it, write it to the new chip, solder the new chip on....the OS would still see the old size, but I figured if I installed OpenWRT just right, because I'm going from stock firmware to OpenWRT, it'd repartition the Nor, if that's the correct word. I don't know a lot about flash.

But the clock speeds don't matter? If one says it can handle a max clock of 50MHz, and another says it can handle a max of 133MHz, that won't matter at all? The faster one will just run at a lower speed?

If this is the case, now I need to find a way to hook a reader / writer up to it. I'll either try to adapt my SPI 8-pin reader / writer to hook up to the 16-pin SOIC, or I'll have to purchase a new reader / writer made for the 16-pin chips.

I was also thinking, if I get this Nor to work right, maybe upgrading the RAM would be the next step. Nor, RAM, and who knows, maybe the world!

**stj** · 08-07-2017, 05:14 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

sector size is the key,
because when flash is written, the o.s. must erase and then write an entire sector at a time.
if the old chip is mostly 4k sectors and the new chip is 64k then your probably in trouble.

now it gets interesting - dump the original flash - or find a FULL dump online.
you want the bootloader.
look at it with a hex editor to see the strings, they often list the chips they support!

**stj** · 08-07-2017, 05:17 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

btw, vizio dont make shit - so who really makes this re-badge??

**ratdude747** · 08-07-2017, 06:40 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

Originally posted by stj

btw, vizio dont make shit - so who really makes this re-badge??

My parents run one (not sure if it's this) that's a rebadged unreleased Linksys model (made while Cisco owned Linksys). Runs OpenWRT quite well actually.

**Spork Schivago** · 08-07-2017, 10:56 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

Originally posted by stj

sector size is the key,
because when flash is written, the o.s. must erase and then write an entire sector at a time.
if the old chip is mostly 4k sectors and the new chip is 64k then your probably in trouble.

now it gets interesting - dump the original flash - or find a FULL dump online.
you want the bootloader.
look at it with a hex editor to see the strings, they often list the chips they support!

Okay. When you were saying sector size was the key, I originally thought you meant the flash needed to be the same physical size. I don't understand why the sector size matters. So long as the kernel has support for the Nor chip that I want to add, wouldn't the module handle all of that? Wouldn't the sector size not matter at all at that point? Are you talking just if the kernel doesn't support the Nor I want to add?

I was lucky enough to find this: https://wiki.openwrt.org/toh/vizio/xwr100

If you look through it, they say there's a serial header at location JP1 and they give the pinouts.

I'm guessing this is for serial console access. If I were to create a serial connection there, during bootup (or using dmesg), would I be able to obtain the information you say I need?

Just so we're on the right page, taking the stock firmware as having a Linux kernel, the Nor chip would have to be either compiled in the kernel or as a module, right? I am compiling the OpenWRT for this router. It, obviously, includes the toolchain to cross compile the various binary packages. Could I use the serial console to replace the kernel on the current Nor with a newer kernel that supports the various Nor chips, in particular, the one that's currently in there, and the one that I want to add?

Now what's preventing me from using a NAND type flash chip? Minus the kernel probably not having support compiled in and no modules, is the pinouts different?

**Spork Schivago** · 08-07-2017, 11:01 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

Originally posted by stj

btw, vizio dont make shit - so who really makes this re-badge??

How would I tell? Crack it open? It's got the Atheros AR7161 and all the WNIC / NICs are Atheros as well....the stock firmware is kinda garbage. Ever run one of those setup CDs to configure a router? That's kinda what the stock firmware is like. Fancy graphics, confusing menus....I think the menu's are meant to "simplify" things, but it kinda has the opposite effect. I'll give an example....

I'm not talking about this router in particular right here, but some routers support repeater mode. But when you go to the configuration page, it says bridge mode. In the real world, bridge mode requires an ethernet cable, repeater mode is for wirelessly repeating the signal. There's been more times than once where we seen these consumer grade routers calling repeater mode bridge mode. That confuses us sometimes. We think certain routers only support bridge mode, but in reality, they're supporting repeater mode.

**diif** · 08-07-2017, 11:22 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

They look to be made by a company called Gemtek.

**Per Hansson** · 08-07-2017, 11:38 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

The Kernel has nothing to do with it.
The CFE (bootloader) needs to support the flash memory.

**Spork Schivago** · 08-07-2017, 06:36 PM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

The CFE (bootloader) would be replaced with one by OpenWRT, wouldn't it? I have the OpenWRT tool to build the firmware. I see sizes and locations in there for the flash that's supposed to be on there....

If the kernel has nothing to do with it, do you know why I see options in OpenWRT's make menuconfig for NAND support? I had three options, Generic (which it's currently set to), Generic Devices with NAND Flash, and then Mikrotik Devices with NAND Flash.

This isn't meant to sound condescending. I'm trying to understand it a bit more.

On my OpenSuSE box, grub2 is the bootloader, and that bootloader loads the kernel. Is it the same with all types of flash? There's a bootloader and it has some sort of module to support the filesystem type (whether it's a hard drive with Ext3 support, Ext4, JFS, etc, or a Nor flash chip, or a NAND flash chip) and boot the kernel?

**Spork Schivago** · 08-07-2017, 06:45 PM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

The tool to create the firmware image that is recognizable as a valid firmware for this specific router has a typedef structure that holds the entry point to the kernel that gets passed to something called RedBoot. Is RedBoot the CFE (bootloader)?

**EDIT: I was looking at a capture of the bootlog (via serial) from the stock firmware, and I think the bootloader is uboot. I'm thinking I could cross-compile uboot and modify it to support the flash, if it doesn't already support it, or maybe find another bootloader to use.

I had assumed the bootloader was built into the firmware. But this might not be the case. If I can get my hands on the source to the bootloader and properly configure it, and if I extract the calibration data from the current flash chip, I wouldn't need to dump the old flash at all. I could write it directly to the new flash chip and solder it on, right?

**stj** · 08-08-2017, 04:02 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

the bootloader is not usually replaced, it starts the box up, and loads the firmware into ram.
so it must know the layout of the memory.

redboot,uboot and cfe are all different bootloaders btw.
redboot is 3rd party - i think redhat made it.
cfe is from broadcom afaik.
not sure about uboot - but it could be vxworks

**stj** · 08-08-2017, 04:31 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

looked at the spec, it wont work.
you usually need atleast twice as much ram as you have flash,
because the bootloader will usually try to copy the flash to ram - 128meg wont fit into 32meg!

the only way i see around that is to change the number of partitions so the boot-stuff is not larger than 16meg, and the rest is used as an extra "user" partition.

**Spork Schivago** · 08-08-2017, 11:40 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

Originally posted by stj

the bootloader is not usually replaced, it starts the box up, and loads the firmware into ram.
so it must know the layout of the memory.

redboot,uboot and cfe are all different bootloaders btw.
redboot is 3rd party - i think redhat made it.
cfe is from broadcom afaik.
not sure about uboot - but it could be vxworks

I didn't realize cfe was an actual bootloader. I thought CFE was the name for bootloaders in general with these embedded devices. Thanks for the clarification!

RedBoot is made by RedHat. I've seen uboot on other devices. The NES Classic (that really small-fits-in-your-hand NES with 20 or 25 built-in games) has it. When we hacked it, we had to download uboot and compile it.

OpenWRT normally doesn't support this router. I found a github repository where a guy created three patches to support it. I cloned the newest version of OpenWRT ( https://github.com/openwrt/openwrt.git ) then I went to his repository

( https://github.com/cmtsij/openwrt/tr...100%4020160725 )

I downloaded the three commits that cmtsij created that adds support for the XWR100 and implemented them into the newest version of OpenWRT. The very first time, I just downloaded his repository. I can compile everything just fine, unless I pick some packages. Then it fails to compile.

So I figured maybe the newest version of OpenWRT would fix this. But it doesn't. I can still compile, so long as I don't actually select any packages. but the moment I select a package, it refuses to compile. The first issue is it's trying to compile gpsd-3.14 and I can see it's using the cross-compiler that I successfully built that comes with OpenWRT. It errors out about not being able to find ncurses/ncurses_dll.h, which ncurses.h is including.

So I check my system to make sure I have the dev files for ncurses installed, and I do. There's the /usr/include/ncurses/ncurses.h file and there's the /usr/include/ncurses/ncurses_dll.h file. When the cross-compiler is trying to compile gpsd, it's using pkg-config to figure out where the header locations are. It passes -I/usr/include/ncurses to the compiler. If I create a symbolic link:
/usr/include/ncurses/ncurses -> /usr/include/ncurses it will compile, but later on, the build fails, because of missing symbols (ncurses symbols).

I think this is wrong though. I don't think it should be using the /usr/include/ncurses files at all. Shouldn't it be using the toolchain's cross-compiler header files? Something like /home/spork/src/vizio_xwr100/staging_dir/target-mips_34kc_musl-1.1.16/usr/include/ncurses.h?

Shouldn't it only be using my system headers when it's actually compiling the cross-compiler, and not the actual packages? I look at the libncurses.so and libncurses.a files using ar. I have to use the cross-compiler's ar utility to see the object files. Obviously, it only works for the .a file and not the so. But am I supposed to have dynamic libraries? I dunno. I tried using ldd to look at the exports, but it seems the cross-compiler didn't create an ldd utility.

Very frustrating.

**Spork Schivago** · 08-08-2017, 11:41 AM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

Originally posted by stj

looked at the spec, it wont work.
you usually need atleast twice as much ram as you have flash,
because the bootloader will usually try to copy the flash to ram - 128meg wont fit into 32meg!

the only way i see around that is to change the number of partitions so the boot-stuff is not larger than 16meg, and the rest is used as an extra "user" partition.

Thank you for looking at this. But couldn't I just upgrade the RAM at the same time? You're right, it does copy the flash to RAM. I saw that but didn't put the pieces together.

**Spork Schivago** · 08-08-2017, 12:06 PM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

Also, it's cgps.o that complains about the undefinied symbols (_nc_COLS), etc. I believe cgps.o gets compiled when gpsd gets compiled. I really think gpsd is pulling in the wrong ncurses.pc pkg-config file and should be actually pulling in the pkg-config .pc file from the cross-compiled ncurses library.

What's a bit odd though, I've checked my system libncurses for the _nc_COLS export, using nm, and I don't see that being exported anywhere. I checked the cross-compiler's libncurses files as well, and don't see it being exported anywheres. I ran grep -R "_nc_COLS" in the /home/spork/src/vizio_wxr100 directory, and there are references to _nc_COLS in the libncurses-5.9 directory....it just never gets compiled into the actual library. Maybe because the cross-compiler's been using some system files instead of the cross-compilers files? I dunno.

I went to the OpenWRT page and saw the required dependencies to compile. They had a command to pull them all in for OpenSuSE 13.2 or something like that. I'm running OpenSuSE Tumbleweed, but installed the dependencies anyways. They said not all packages (feeds) use git, some use subversion and mercurial or whatever it's called and they should be installed in order to update the various feeds. Maybe I should run the ./scripts/feeds update -a and ./scripts/feeds install -a commands again, now that I have subversion and mercurial installed.

**stj** · 08-08-2017, 02:05 PM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

you may be able to change the ram chip(s) if the extra address lines are on the board - sometimes they are - sometimes not.

**Spork Schivago** · 08-08-2017, 02:46 PM

Re: Upgrading NOR Flash on a Vizio XWR100 router.

What do you mean by the extra address lines? Large sized RAM requires extra lines? If this is the case, then the NAND and CPU would require them as well, I'd think.

If i'm not going for a super increase (ie, increasing it from 32 MB to 64MB vs 32 MB to 1GB), I might be okay?

How do I determine how many address lines are required based on the size of the stick of RAM? Would it be something like:

Code:

32 MB = 32 * 1024KB = 32 * 1024 * 1024 bytes = 2^5 * 2^10 * 2^10 = 2^25

25 address bits?

How do you easily find the 2^5? I never really got into logarithms (I only took up to pre-calc but dropped out of pre-calc).

Is it something like log(x) / log(2), where x is the size of the memory, in this case, 32?

Code:

log(32) = 1.5051499783199059760686944736225
log(2) = 0.30102999566398119521373889472449

log(32) / log(2) = 5

If that's correct (checks out on the calc, but might just be a coincidence), then for 64MB, we'd need:

Code:

log(64) / log(2) = 6

address_lines = (2^6) * (2^10) * (2^10)
(2^6) * (2^10) * (2^10) = 67,108,864

address_lines = log(67,108,864) / log(2) = 26

address_lines = 26?

**check**
2^26 = 67,108,864

Is that right?

Upgrading NOR Flash on a Vizio XWR100 router.

Upgrading NOR Flash on a Vizio XWR100 router.

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