Modding Sagemcom F@ST 1704

Hardware Questions and Recommendations
1

Hello,
First of all, this is the device wiki page.

I am modding Sagemcom F@ST 1704 to add OpenWrt support because the current hardware specs are not sufficient for most builds.
I am willing to replace the SPI flash with a larger one 25L12835F
and the RAM is too low for a newer OpenWrt build.
So I am willing to change it too.
64MB will be enough, I guess.
After looking for a higher capacity than 16MB, some sources warned that it won't work because of some CPU limitations.

The question is, can a Broadcom BCM6338 CPU handle 64MB of RAM without modifying anything
or if it's necessary to do some tweaks to the CFE bootloader.
and if the new SPI flash chip will be compatible without any issues.

2

You should consider if it's really worth it.

I'd suggest just trying to get OpenWrt installed in the current hardware. You'll need to do a significant level of development yourself already.

I don't think there will be any appetite to accept into mainline OpenWrt a configuration for a board that requires significant part replacement just to operate. So you'd end up having to support your own hardware 'out of tree' already.

Looking at that chip spec
CPU1 Speed: 240 MHz
It's not going to give very good performance for anything that requires CPU (like encryption / data transfers that can't fully leverage DMA).

For the time and effort in modding RAM / FLASH on this board, you could likely buy a much much much more capable unit...

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3

Openwrt on this era routers is slow as heck, not worth it.

1 Like
4

I totally agree what you say.

Yes, I am not going to install any new version of OpenWrt on it. I just want to learn how it works.
I am doing this upgrade for educational purposes and not looking at any good performance.
I might use this router for testing.
I already have a fully working mid-range openwrt router.

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