[OpenWrt-Devel] Netgear R6260 EEPROM location

David Bauer mail at david-bauer.net
Thu Jan 30 06:36:49 EST 2020


Hello again,

On 1/30/20 1:11 AM, David Bauer wrote:
> Yes, I've checked the partitioning (and it is off). However, I still opted to push the
> other fix, as I'm unsure whether or not the partition mapping is off for all boards or only
> my specific R6260, as the partition map seems to stored on the device in the SC_PART_MAP
> partition instead of the kernel. So it could be entirely possible, that this differs between
> different models, thus we would never have a "correct" partition mapping.
> 
> However, in this case WiFi would have been broken for the beginning. But as the R6260 was introduced
> as "Same board, different labling", i count the chance of WiFi being broken from the beginning as
> high, especially as the Radio transmits, but VHT modes are nonsense and throughput is abysmal.
> 
> See /proc/mtd below - partitions are in order:
> 
> # cat /proc/mtd
> dev:    size   erasesize  name
> mtd0: 00100000 00020000 "Bootloader"
> mtd1: 00100000 00020000 "SC_PART_MAP"
> mtd2: 00400000 00020000 "Kernel"
> mtd3: 02800000 00020000 "Rootfs"
> mtd4: 00200000 00020000 "English UI"
> mtd5: 00220000 00020000 "ML1"
> mtd6: 00200000 00020000 "ML2"
> mtd7: 00200000 00020000 "ML3"
> mtd8: 00200000 00020000 "ML4"
> mtd9: 00200000 00020000 "ML5"
> mtd10: 00200000 00020000 "ML6"
> mtd11: 00200000 00020000 "ML7"
> mtd12: 00200000 00020000 "ML8"
> mtd13: 00200000 00020000 "ML9"
> mtd14: 00200000 00020000 "ML10"
> mtd15: 00200000 00020000 "ML11"
> mtd16: 00200000 00020000 "Factory"
> mtd17: 00220000 00020000 "SC Private Data"
> mtd18: 00200000 00020000 "POT"
> mtd19: 00200000 00020000 "Traffic Meter"
> mtd20: 00200000 00020000 "SC PID"
> mtd21: 00200000 00020000 "SC Nvram"
> mtd22: 00200000 00020000 "Ralink Nvram"
> mtd23: 00200000 00020000 "Reserved Block1"
> mtd24: 00200000 00020000 "Reserved Block2"
> mtd25: 00200000 00020000 "Reserved Block3"
> mtd26: 00200000 00020000 "Reserved Block4"
> mtd27: 00200000 00020000 "Reserved Block5"
> mtd28: 02140000 00020000 "Reserved Block6"
> 
> So I'm waiting on feedback from other owners of these boards and using this
> (more or less) strange fix in the meantime.

Robert complained in the meantime, that my fix broke his R6260. He also sent me
the partition map of the stock firmware and it differs from mine (see below).

dev:    size   erasesize  name
mtd0: 00100000 00020000 "Bootloader"
mtd1: 00100000 00020000 "SC_PART_MAP"
mtd2: 00400000 00020000 "Kernel"
mtd3: 02800000 00020000 "Rootfs"
mtd4: 00200000 00020000 "English UI"
mtd5: 00200000 00020000 "ML1"
mtd6: 00200000 00020000 "ML2"
mtd7: 00200000 00020000 "ML3"
mtd8: 00200000 00020000 "ML4"
mtd9: 00200000 00020000 "ML5"
mtd10: 00200000 00020000 "ML6"
mtd11: 00200000 00020000 "ML7"
mtd12: 00200000 00020000 "ML8"
mtd13: 00200000 00020000 "ML9"
mtd14: 00200000 00020000 "ML10"
mtd15: 00200000 00020000 "ML11"
mtd16: 00200000 00020000 "Factory"
mtd17: 00200000 00020000 "SC Private Data"
mtd18: 00200000 00020000 "POT"
mtd19: 00200000 00020000 "Traffic Meter"
mtd20: 00200000 00020000 "SC PID"
mtd21: 00200000 00020000 "SC Nvram"
mtd22: 00200000 00020000 "Ralink Nvram"
mtd23: 00200000 00020000 "Reserved Block1"
mtd24: 00200000 00020000 "Reserved Block2"
mtd25: 00200000 00020000 "Reserved Block3"
mtd26: 00200000 00020000 "Reserved Block4"
mtd27: 00200000 00020000 "Reserved Block5"
mtd28: 02180000 00020000 "Reserved Block6"

I'm still waiting for him to send ma a photo of the routers backside, but it seems
we have to dynamically detect the partition map of the devices. I'll look into the
SC_PART_MAP partition and the routers GPL code to find a possible solution for this
problem.

In the meantime, I'll revert my "fix" to not break existing boards.

For the record: I assume this bug has nothing to do with the partition shifting
seen on the R6220, as the offending "feature" of the mtknand driver was disabled
in the meantime (and the partition map differs in the stock firmware). [0]

[0] https://github.com/openwrt/openwrt/pull/1304

Best wishes
David

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