error: could not load android-info.txt

It depends on how the flash all script is organized. Try flashing into the partition directly.

Eg: fastboot flash system system.img

I observed this issue when trying to fastboot update an OTA package.

Eg: fastboot update xyz.zip.

Currect way to update via fastboot is

fastboot update updateImagename.img

Old thread so sorry for reactivating it, but it's still one of the top hits and it's unanswered. My fix was to ensure I had the ANDROID_PRODUCT_OUT environment variable, and that it was pointing to /home/{usr name}/{build directory}/out/target/product/{taget}

Again, sorry for resurrecting a dead post.

As $fastboot flashall -w

flash the Rom on connected device it needs to know which Run/Device/Product you want to flash as there might be many products available in out/target/product directory, And so product is obtained by ANDROID_PRODUCT_OUT variable which should point to any product i.e.

/home/{usr name}/{build directory}/out/target/product/{taget}

And to set the ANDROID_PRODUCT_OUT we just need to do:

source build/envsetup.sh 
lunch

and choose your product in lunch menu, so that fastboot flashall -w would know which product you wanna flash.