[OpenWrt-Devel] Trunk tl wdr4900 v1 boot fails on bootloader CRC check

[Alberto Bursi]

On 10/03/19 22:33, Sami Olmari wrote:
>
> On Sun, Mar 10, 2019 at 4:20 PM Alberto Bursi 
> <bobafetthotmail at gmail.com <mailto:bobafetthotmail at gmail.com>> wrote:
>
>
>     On 10/03/19 21:32, Sami Olmari via openwrt-devel wrote:
>     > Okay it wasn't
>     >
>     https://github.com/openwrt/openwrt/commit/576c69938bb38c7edfa23f220eb30cb5c1d0a726
>
>     > nor the immediately next one
>     >
>     https://github.com/openwrt/openwrt/commit/0fbd3d23aadee0d95beef4f077a866dae7f4841a
>
>     > so it's still unclear what commit really breaks this... but I'll
>     try
>     > to keep looking.. :)
>     >
>     > --
>     >  Sami Olmari
>     > _______________________________________________
>     > openwrt-devel mailing list
>     > openwrt-devel at lists.openwrt.org
>     <mailto:openwrt-devel at lists.openwrt.org>
>     > https://lists.openwrt.org/mailman/listinfo/openwrt-devel
>
>
>     The issue isn't a specific commit.
>
>     The issue is the kernel is too big.
>
>     The bootloader of this device only reads 0x29F000 bytes in hex or
>
>     2748416 bytes, around 2.6Mb in decimal.
>
>
>     In the Github PR (1) they see they can only work around this by
>
>     making an u-boot bootloader that can be loaded instead of the kernel.
>
>     Then this u-boot will load the kernel with no limitations.
>
>
>     -Alberto
>
>
>     [1] https://github.com/openwrt/openwrt/pull/1773
>
>
>
> Shouldn't this alleviate that? 
> https://github.com/openwrt/openwrt/commit/576c69938bb38c7edfa23f220eb30cb5c1d0a726
>
> "
> Currently, the image creation process for the TP-Link tl-wdr4900-v1
> needs a fixed sized kernel and places the rootfs partition at a
> fixed offset. With the upcoming move to 4.19 the kernel will no
> longer fit into the existing allocated space for the kernel
> partition.
>
> This patch converts the device to utilize the established
> tplink,firmware mtdsplitter, which can deal with a dynamic
> kernel/rootfs size.
>
> "
>
> Not that I really know too good, I'm still just eager user more than developer... Anyway, All I can then hope a fix is introduced... I am more than willing to alpha/betatest :)
>
> -- 
>   Sami Olmari


No it does not. That patch solves kernel size issue for OpenWrt, but not 
for bootloader.

The bootloader will still only read 2.6MB from flash, where the kernel 
partition was in stock firmware.

If the kernel is bigger than that, it will not be all read and will fail.

This is why they want to make a second u-boot bootloader,

so the main bootloader will load and execute the second bootloader

that will then load and execute the kernel. Other devices in OpenWrt do 
this, it's not a new thing.

Follow the Github PR thread and see if they can fix this.

-Alberto

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