When running Linux i am able to use SP flash tool to do a readback from my mediatek device and do a full backup of the rom images while the device is in preloader mode, without the use of any additional USB drivers.

Yet this is not possible with Google Pixel.

Is this perhaps due to Mediatek going out of their way and adding support for their devices during the development of the mainline linux kernel and Google dont?

  • Mediatek is very strong in the market of custom Android based devices for non-smartphones (Android on IoT and other embedded devices). I would assume that the possibility to read and write images from "outside" of the device is a convenience method added by Mediatek for simply device development as it reduces the possibility to brick your device.
    – Robert
    Aug 21, 2020 at 11:37
  • But why does why does Linux not need additional USB drivers to do this, whereas in windows we need Mediatek's VCOM drivers? Aug 21, 2020 at 11:54
  • 1
    On Windows you always need (USB) drivers for a device even if windows already contains the driver binaries (INF file maps USB-ID to driver). Linux contains alreayd a large number of generic drivers. But such questions are off-topic here as it does not have anything to do with Android.
    – Robert
    Aug 21, 2020 at 12:14
  • Cross posting: unix.stackexchange.com/q/605563/262728 Aug 21, 2020 at 13:43

1 Answer 1


it is simply not true that linux does not need drivers. linux is just smarter than windows and handles it's drivers itself. linux just doesn't ask for drivers, but it use drivers anyway

new mediatek devices are accessable from preloader only with proper secure boot download agent (DA_SWSEC.bin) and authentification file (auth_sv5.auth). that files are vendor and device specific. even with proper files SP Flash Tool is not able to read back whole EMMC, there are forbidden partitions which can't be accessed. Lenovo devices are a good example

for qualcomm devices it is quite same, there we have EDL mode available instead where we can read raw partitions from device only with proper factory loader (firehose programmer). again that files are vendor and device specific

the fact that you can't read data from google pixel is that HTC hasn't released/leaked firehose programmer for google devices

while google may have that file internally, it seems they are not interested in unbricking, the official install method rely on fastboot only. once a device becomes bricked, it is not possible to unbrick (on locked bootloader). so the official solution for bricked google devices is a replacement device. that's why i personally recommend every google device should be bootloader unlocked on initial setup (my opinion)

  • How does i find out if a device has secure boot enabled as i have tried to check for this when starting the device in recovery mode but it doesnt mention anything regarding secure boot? Aug 23, 2020 at 18:34
  • fastboot getvar secure returns if the bootloader is locked/unlocked, is that right? I thought a device specific DA file is required to flash images onto the device regardless if the bootloader is locked or unlocked. Aug 23, 2020 at 20:57
  • 1
    yes secure boot is independent from bootloader status. but you can flash from fastboot mode without DA on unlocked bootloader, secure boot DA concerns SP Flash Tool in preloader mode only. fastboot getvar unlocked returns the bootloader status. fastboot getvar secure returns the secure boot status. fastboot getvar all returns all information
    – alecxs
    Aug 23, 2020 at 21:01
  • blog.hovatek.com/…
    – alecxs
    Aug 23, 2020 at 21:07
  • Does using a universal download agent allow the user to readback parts of the eMMC and just not the forbidden partitions, or would the user completely not be able to do a readback of anything ? Aug 24, 2020 at 10:17

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