[LEDE-DEV] [PATCH] ar71xx: add support for TP-Link TL-WDR7500v6

[Piotr Dymacz]

Hello Bill,

On 29.11.2017 20:17, Bill Moffitt wrote:
> Hello Piotr and Karol,

[snip]

>>>> Please, include in commit message how to install LEDE on this device as
>>>> described under "commit description" section on [1].
>>>
>>> Ok, will prepare manual how to change bootloader to non-RSA one, move 
>>> art and
>>> install LEDE.
>>
>> I'm sorry but I'm against accepting support for devices which requires 
>> such invasive modifications. We always try to make it possible for 
>> users to get back to the stock firmware which wouldn't be easy (or 
>> possible at all) with your changes in mtd layout and after bootloader 
>> swap.
>>
> In general, of course, I agree. However, we are seeing an increasing
> number of vendors (TP-Link and Ubiquiti, to name 2) using some form of
> locking in the bootloader to prevent loading of third-party firmware.

Then buy and use hardware from vendors who are open source friendly and 
allow users to actually fully own the hardware they paid for! :)

> The only option for loading OpenWRT (permanently - not using initramfs)
> on these devices will be replacing the bootloader, as Karol does in this
> patch.

Swapping bootloader isn't the only issue I see here. Moving ART which is 
essential and unique per device might end up in a data loss which cannot 
be recovered in any way.

> If the only objection is that it involves invasive modifications that
> may not (probably won't) allow the device to be re-flashed to stock, I
> would prefer we accept the patch and make a very strongly-worded note in
> the ToH and the device's wiki page explaining the situation.

This is not the only one objection. Personally I don't have problems 
with swapping bootloader and for ar71xx target we already have a 
dedicated package with old U-Boot sources: [1]

The problem here is that the bootloader the user has to use for this 
device comes from some random GitHub repository which exist today but 
may disappear tomorrow. Who will make sure that the bootloader image the 
author of the support mentions in his patch will be still available in 
next years and is correct and won't break users device?
If the bootloader code was in our repository or in upstream, I would be 
first one accepting support for this device.

What's also important to notice here, devices with QCA WiSoCs and SPI 
NOR flash chips aren't easy to recover from a failed bootloader flash. 
If there is no JTAG on the board the only way to bring device back to 
life is to use flash chip programmer.

[1] 
https://github.com/lede-project/source/tree/master/package/boot/uboot-ar71xx

-- 
Cheers,
Piotr

> 
> FWIW,
> 
> Bill
> 
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