Some hardware makes use of closed source firmware blobs that cannot be replaced by open source firmware. Is it advisable to temporarily revert to newer original manufacturer firmware versions once in a while in order to keep this firmware up to date? Or doesn't this make a difference?
it should be advisable to ignore support for such manufacturers
I understand your reasoning, but I own a TP-Link Archer C7 V2, so that's what I'm dealing with right now. I do want to keep LEDE installed, but I'd like to know if the oem firmware typically includes updated firmware blobs. Since they are there anyway, I'd like to keep them up to date.
Hmm. I don't get the question. Which part of the OEM blog stays intakt and is used by LEDE once LEDE is installed? Is there's some purely binary "baseband radio" like every smart phone has which runs parallel to LEDE? That would be the only situation where "revert my device to OEM and reinstall LEDE in order to gain new binaries" would be a thing.
I don't remember where I originally read it, but the way I understand it is that at least the 5 GHz radio is controlled by its own firmware and LEDE communicates with this firmware, but does not replace it. So I'm guessing that that's indeed the case, but I hope someone knows for sure.
Don't know, if this is the answer for all routers, but seems most routers nowadays use "fullmac" chips for wifi, most probably all that have a 5GHZ radio.
Fullmacs are all-in-one-chips with their own onboard ARM processor and its own RAM and an own ROM, the ROM containing proprietary firmware for the wifi chip.
As far as I know, usually these chips do not have flashable ROMs. So if there are firmware bugs contained, the chip firmware cannot be upgraded by flashing the ROM.
The chip vendors solve this, by providing differential-binary BLOBs, that need to be loaded into the chip's RAM, these redefine the problematic code parts of the chip's ROM code.
The device OS and it's wifi driver is made responsible to upload these BLOBS to the wifi chip on every device restart, when the wifi driver is loading.
E.g. the recent Broadcom wifi issue of many iOS devices and Macbook's was such a case: Even the Macbook Bootcamp drivers had been patched for this, such that even if you boot Windows natively on the Macbook, the driver makes sure that the Broadcom wifi flaw is in a patched state during Macbook operation.
I am not gifted at all with LEDE development, but I've noticed that a recent LEDE version on one of my routers has a "/lib/firmware" folder, which actually contains such proprietary BLOB objects for the router wifi chip.
So it will not help to revert back to an original vendor firmware from time to time, as any wifi BLOB patch is not applied permanently. You only need to have an up-to-date LEDE firmware applied for your device that contains the most recent BLOB updates for your router's wifi chip (if it's a fullmac chip). LEDE will then patch the wifi's ROM bugs on the fly when initializing the wifi chip after every device restart. I have no idea where LEDE developers get the most recent firmware BLOBS for the different wifi chips. I've read that some vendors actively support LEDE/OpenWRT development for this.
Thank you, very informative. This answers my question.
For most devices it's https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/