[Fire HD 8 and HD 10 Original Android Development] finwefeanor:
I finally managed to install TWRP and then lineage os. Great tut [MENTION=10911591]deverro[/MENTION] ! I will write some steps as I see necessary to mention them, will explain deverro's method people who use linux with VM like me.

after sudo brick-9820.sh and when it says something like this on tablet screen : " success! now unplug the tablet and turn it off before bootrom-step.sh ", below part was most problematic especially bald part.

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sudo ./bootrom-step.sh

// this will take some time (in my case around 5-10 minutes)

// will give you message similar to "awaiting device connection" and nothing else...

// although nothing seems to happen, just wait a bit and watch the terminal, it will soon start displaying the process

// it should then reboot the tablet, but in my case, that did not happen, so i had to do it manually...

// NOTE that althought tablet seems to be "off", it isn't, so press power btn and hold for 5 sec to turn it off

// after that click and hold volume up button (when in portrait mode it is the right one, the one closest to power btn)

// and immediately after that press and hold the power btn until amazon logo shows itself

// it should then show in bottom left corner HACKED FASTBOOT after a few seconds

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when I turned off tablet and run " sudo ./bootrom-step.sh " on terminal and plug the cable, nothing happened. I waited like 30 mins it didn't boot, and also it didn't recognize my device. Because in VM, you need to add usb filter after every step ( first was at the beginning after adb reboot bootloader , it didnt see my device when I typed fastboot devices ) in my case there are 4 usb filters total - 1) Amazon Fire , 2) Amazon Android, 3) MediaTek Inc MT6227 phone, 4) Amazon omni_douglas

After I add usb filters, I was stucked again at bald line on deverro's mentioned point, because like he said blank screen fools you. You might not understand if it is on or off. I tried to close it (but I didn't know it is close or open at that point so tried many times) In my case volume btn down + power worked If I recall correctly.

If you can manage to open tablet with volume btn up (or down) + power btn , bootrom-step command should work and you need to see this processing line:

[2020-01-16 15:07:06.924612] Waiting for bootrom

[2020-01-16 15:07:17.979473] Found port = /dev/ttyACM0

[2020-01-16 15:07:17.979796] Handshake

* * * If you have a short attached, remove it now * * *

* * * Press Enter to continue * * *

[2020-01-16 15:07:29.000116] Init crypto engine

[2020-01-16 15:07:29.017653] Disable caches

[2020-01-16 15:07:29.018011] Disable bootrom range checks

[2020-01-16 15:07:29.031558] Load payload from ../brom-payload/build/payload.bin = 0x4888 bytes

[2020-01-16 15:07:29.033404] Send payload

[2020-01-16 15:07:29.583997] Let's rock

[2020-01-16 15:07:29.584711] Wait for the payload to come online...

Another problem occured for me: ( don't know if it is the same for everyone or it is because VM )

At this state, micro usb cable automatically plugged in and plugged out in some constant time like in every 15 - 20 secs or so. I mean you hear the sound of usb cable plugged in to your laptop, after some time you hear plugged off and this cycle continues while usb cable remain attached to your tablet. So the processing line that starts with " Init crypto engine" couldn't finish because in the middle of the process you hear usb cable plugged off sound and line gives error (like " FAILED no such device" something like that)

So if this happens to you, you need to be fast.

when device is off and unplugged after brick-9820 command,

* Run "sudo ./bootrom-step.sh"

* plugged usb cable

* immediately open tablet with volume btn up + power btn (do not waste time at this point, might need couple times trying to be on exact timing)

* when you see

[2020-01-16 15:07:06.924612] Waiting for bootrom

[2020-01-16 15:07:17.979473] Found port = /dev/ttyACM0

[2020-01-16 15:07:17.979796] Handshake

* * * If you have a short attached, remove it now * * *

* * * Press Enter to continue * * *

press enter immediately. If you do this fast, process will reach flashing parts and after that you won't hear unplugged usb sound.

After this continue to follow rest of deverro's steps.

I don't know that usb cable sound part is because of my 3rd party cable or not. Maybe because it is in bricked state that's why.

You all might know or experienced what I explained I am new at this things. But this was the most difficult part so I wanted to mention besides blank screen.

Deverro you are like fallout level 100 science skill perk.