Adding support for DLink DSL 3580L

For Developers
1

I am adding support for DLink DSL 3580L (broadcom 6362 with integrated wifi + bcm4352 variant mini-pcie), i have successfully run an image that do not crash and have working ethernet, if someone is interested on helping the port, please check https://github.com/aleferri/openwrt-dsl3580l.

I am also looking for information on the strange flash layout i found, the router has 16 MB flash, checked visually by looking at the chip soldered, but also reported by the dmesg, but the stock firmware use just 7.5 MB of space, and just after CFE + stock there are 4 different areas, one 1.5 Mb non-erased block with high entropy, one erased block of around 7 MB, some padding with low entropy and then the broadcom nvmem, maybe some of you encountered a similar layout somewhere else and can explain its purpose

2

That sounds a lot like a split firmware image. It's common for a device to store two firmware images to flash in case one of them gets corrupt. After you make a backup of the whole flash, you should be able use to space occupied by the two vendor OS images for a single openwrt one.

3

After i found the bin of the original firmware, i think i got it, the 1.5 MB block with high entropy is the linux kernel, because the firmware image has the kernel at the end of rootfs, instead of using openwrt convention (kernel at start + rootfs after), so, the 7.5MB + 1.5 MB = 9 MB occupied for original firmware, so i can safely override that block too