C760 Replace Bad Nand Chip

[dmarschal]

Hello,
Have any of you replaced the NAND chip in a C760?

The NAND chip is a Samsung K9K 1G08 UOM-YCB0. This is an 'slc die stack' module.

The K9K is hard to get but the K9F series (slc normal) is widely available and much cheaper.

Let me know your thoughts.

Thank you!

[utx]

The K9K is hard to get but the K9F series (slc normal) is widely available and much cheaper.

I am afraid that K9K has 2kB memory pages, but K9F has 0.5kB memory pages.

It is easy to change this setup in the kernel but I have no idea whether the bootloader ROM is able to boot from 2k pages.

SL-C3200 has K9F memories, but the service manual mentions K9K memories. The kernel handles special NAND layout by static struct nand_ecclayout akita_oobinfo. I don't see it for other models.

[dmarschal]

Thank you utx,

I bought F9F and F9K series chips to test. I will report back if the K9F works.

I found the following strings in mainte.bin

Code: [Select]

1132c TOSHIBA TC58512FT
11340 TOSHIBA TC58DVG02AFT
11358 SAMSUNG K9F1208U0M
1136c SAMSUNG K9K1G08U0M
Does it mean the SAMSUNG F9F series is supported only in 64Mx8 bit size?

I think it would be possible to modify mainte.bin to accept other flash IDs.

On "C+D" menu and "CF update" in "D+M" menu, both LEDs are on for a second or two then they start blinking. What does this exactly mean?
(I'm checking the code in mainte.bin and diag.bin to find it out. flash code starts at 0xbc554, mainte loaded at 0x0, diag.bin loaded at 0x7c000)

BTW the 'NAND Bad Count' gives me 8192 blocks with a nice

Code: [Select]

ERROR! No partition info
code=(610)message. I think it's dead.

Sorry for the lots of questions. I know these machines are very old but I could not find a replacement.

[utx]

Does it mean the SAMSUNG F9F series is supported only in 64Mx8 bit size?

Blindly guessing, that other sizes may be possible as well. Only 8 bits are wired. But I may be wrong and only selected memory types are recognized.

But there are two Flash slots. One is empty. So you may be able to solder twice more NAND flash.

I think it would be possible to modify mainte.bin to accept other flash IDs.

It will not help. First stage boot runs from PROM (at least on SL-Cxx00 models). It loads second stage boot from NAND. If NAND flash chip is not recognized, second stage boot never happens.

You would need to replace PROM by NOR flash to be able to change flash IDs. (And you would need to know the checksum algorithm to keep it running.)

Only modern OneNAND chips (that did not exist in time of Zaurus release yet) support cold booting.

On "C+D" menu and "CF update" in "D+M" menu, both LEDs are on for a second or two then they start blinking. What does this exactly mean?
(I'm checking the code in mainte.bin and diag.bin to find it out. flash code starts at 0xbc554, mainte loaded at 0x0, diag.bin loaded at 0x7c000)

BTW the 'NAND Bad Count' gives me 8192 blocks with a nice

Code: [Select]

ERROR! No partition info
code=(610)message. I think it's dead.

Well, I don't know, what LEDs mean.

You can run diagnostics from the PROM. In the default setup, it is exactly the same as the NAND diagnostics (again on SL-Cxx00 models, I don't know SL-Cxx0 models), but it is capable to run even in case of totally broken NAND. I don't remember the key combination exactly, but I am guessing something line Fn+D+M. (You can find it somewhere in forum.)

Partition info is part of one of the first blocks of the NAND. It exists there in many copies for the case of broken blocks. If all reserved blocks are broken, Zaurus is not capable to find the partition table.

You can run ROM diag, try to reflash fresh NAND image, and see whether it will work.

[dmarschal]

Does it mean the SAMSUNG F9F series is supported only in 64Mx8 bit size?

Blindly guessing, that other sizes may be possible as well. Only 8 bits are wired. But I may be wrong and only selected memory types are recognized.

But there are two Flash slots. One is empty. So you may be able to solder twice more NAND flash.

I think it would be possible to modify mainte.bin to accept other flash IDs.

It will not help. First stage boot runs from PROM (at least on SL-Cxx00 models). It loads second stage boot from NAND. If NAND flash chip is not recognized, second stage boot never happens.

You would need to replace PROM by NOR flash to be able to change flash IDs. (And you would need to know the checksum algorithm to keep it running.)

Only modern OneNAND chips (that did not exist in time of Zaurus release yet) support cold booting.

On "C+D" menu and "CF update" in "D+M" menu, both LEDs are on for a second or two then they start blinking. What does this exactly mean?
(I'm checking the code in mainte.bin and diag.bin to find it out. flash code starts at 0xbc554, mainte loaded at 0x0, diag.bin loaded at 0x7c000)

BTW the 'NAND Bad Count' gives me 8192 blocks with a nice

Code: [Select]

ERROR! No partition info
code=(610)message. I think it's dead.

Well, I don't know, what LEDs mean.

You can run diagnostics from the PROM. In the default setup, it is exactly the same as the NAND diagnostics (again on SL-Cxx00 models, I don't know SL-Cxx0 models), but it is capable to run even in case of totally broken NAND. I don't remember the key combination exactly, but I am guessing something line Fn+D+M. (You can find it somewhere in forum.)

Partition info is part of one of the first blocks of the NAND. It exists there in many copies for the case of broken blocks. If all reserved blocks are broken, Zaurus is not capable to find the partition table.

You can run ROM diag, try to reflash fresh NAND image, and see whether it will work.

utx, thank you so much for the detailed info!

In the mean time I was able to make my C760 work. The D+M diag+NAND clear/test did the trick.

The flash code in diag.bin checks for one manufacturer ID only. It reads out all four ID bytes and uses them so it might be possible to add a double size Samsung chip. (It's fun to work with flash memories again. We've made 512kb flash memory cards using a Fujitsu 29LV chip for the Atari Portfolio years ago.)

The PROM is an Intel 28F chip, at least in a C760 and it seems it has software-locked sectors.

Again, thank you so much.

[utx]

so it might be possible to add a double size Samsung chip.

Maybe double size, but not double bus width. Looking at the SL-C3100 schematics, only 8 data lines are wired.

The PROM is an Intel 28F chip, at least in a C760 and it seems it has software-locked sectors.

According to the documentation of SL-C3100, LH28F640B (Sharp-NorFlash64Mb) or 28F256L30 (Intel-SynNorFlash256Mb) can be used instead of MR27T6312G-XXXTP (Oki-P2ROM-64Mb-withOTP) (both have a dedicated open position on the PCB).

You can find more datasheets on my datasheets page.