[Fire HD 8 and HD 10 Q&A, Help & Troubleshooting] MontysEvilTwin:
Unfortunately my attempt has ended in failure. I downloaded amonet-douglas-v1.2 (see here: https://xdaforums.com/showpost.php?p=80154797&postcount=1) and replaced the LK, TZ, and preloader images in the 'bin' folder with those from the latest version of FIre OS for giza (5.3.6.4). I also edited the 'Step-1' and 'Step-2' scripts to allow them to run on the giza (HD 8, 2016). I ran Step-1. Output here:

x@x:~/Downloads/amonet-giza-t2/amonet$ sudo ./step-1.sh
* daemon not running. starting it now on port 5037 *
* daemon started successfully *
Testing root access...
uid=0(root) gid=0(root) context=u:r:init:s0

PL version: 6 (6)
LK version: 1 (2)
TZ version: 258 (259)

Your device will be reset to factory defaults...
Press Enter to Continue...

Dumping GPT
34+0 records in
34+0 records out
17408 bytes transferred in 0.001 secs (17408000 bytes/sec)
97 KB/s (17408 bytes in 0.174s)

Modifying GPT
[2020-06-23 12:47:56.140090] Input GPT:
[2020-06-23 12:47:56.155798]
[2020-06-23 12:47:56.165320] Sector size (logical): 512 bytes
[2020-06-23 12:47:56.181377] Disk identifier (GUID): 0977B6B6-2B39-4075-8CCF-F0F9A3D117CD
[2020-06-23 12:47:56.187570] Partition table holds up to 128 entries
[2020-06-23 12:47:56.192110] This partition table begins at sector 2 and ends at sector 33
[2020-06-23 12:47:56.196498] First usable sector is 34, last usable sector is 30777310
[2020-06-23 12:47:56.201418] Other partition table is at sector 30777343
[2020-06-23 12:47:56.207044]
[2020-06-23 12:47:56.212063] Number Start (sector) End (sector) Size Name
[2020-06-23 12:47:56.270255] 1 1024 7167 3.00 MiB proinfo
[2020-06-23 12:47:56.280114] 2 7168 17407 5.00 MiB nvram
[2020-06-23 12:47:56.294441] 3 17408 37887 10.00 MiB protect1
[2020-06-23 12:47:56.315751] 4 37888 58367 10.00 MiB protect2
[2020-06-23 12:47:56.327317] 5 58368 58879 256.00 KiB seccfg
[2020-06-23 12:47:56.338008] 6 58880 59879 500.00 KiB lk
[2020-06-23 12:47:56.348155] 7 59880 92415 15.89 MiB boot
[2020-06-23 12:47:56.364741] 8 92416 125183 16.00 MiB recovery
[2020-06-23 12:47:56.375237] 9 125184 137471 6.00 MiB secro
[2020-06-23 12:47:56.385676] 10 137472 138495 512.00 KiB para
[2020-06-23 12:47:56.403211] 11 138496 154879 8.00 MiB logo
[2020-06-23 12:47:56.414057] 12 154880 175359 10.00 MiB expdb
[2020-06-23 12:47:56.423967] 13 175360 177407 1024.00 KiB frp
[2020-06-23 12:47:56.446425] 14 177408 187647 5.00 MiB tee1
[2020-06-23 12:47:56.457419] 15 187648 197887 5.00 MiB tee2
[2020-06-23 12:47:56.466734] 16 197888 278527 39.38 MiB metadata
[2020-06-23 12:47:56.486107] 17 278528 280575 1024.00 KiB kb
[2020-06-23 12:47:56.501732] 18 280576 282623 1024.00 KiB dkb
[2020-06-23 12:47:56.511501] 19 282624 3588671 1.58 GiB system
[2020-06-23 12:47:56.534411] 20 3588672 4457023 424.00 MiB cache
[2020-06-23 12:47:56.545231] 21 4457024 4458047 512.00 KiB MISC
[2020-06-23 12:47:56.554629] 22 4458048 4490815 16.00 MiB persisbackup
[2020-06-23 12:47:56.572927] 23 4490816 4499455 4.22 MiB PMT
[2020-06-23 12:47:56.583723] 24 4499456 30777310 12.53 GiB userdata
[2020-06-23 12:47:57.130509]
[2020-06-23 12:47:57.135884] Regenerate primary and backup GPT from input
[2020-06-23 12:47:57.140959] Writing regenerated GPT to gpt-G000KW0463310950/gpt.bin.gpt
[2020-06-23 12:47:57.272546] Writing regenerated backup GPT to gpt-G000KW0463310950/gpt.bin.bak
[2020-06-23 12:47:57.296137] Writing backup GPT offset to gpt-G000KW0463310950/gpt.bin.offset
[2020-06-23 12:47:57.325285]
[2020-06-23 12:47:57.330897] Modified GPT Step 1:
[2020-06-23 12:47:57.351999]
[2020-06-23 12:47:57.358603] Sector size (logical): 512 bytes
[2020-06-23 12:47:57.364570] Disk identifier (GUID): 0977B6B6-2B39-4075-8CCF-F0F9A3D117CD
[2020-06-23 12:47:57.369705] Partition table holds up to 128 entries
[2020-06-23 12:47:57.374261] This partition table begins at sector 2 and ends at sector 33
[2020-06-23 12:47:57.378757] First usable sector is 34, last usable sector is 30777310
[2020-06-23 12:47:57.383981] Other partition table is at sector 30777343
[2020-06-23 12:47:57.389786]
[2020-06-23 12:47:57.396300] Number Start (sector) End (sector) Size Name
[2020-06-23 12:47:57.413002] 1 1024 7167 3.00 MiB proinfo
[2020-06-23 12:47:57.429682] 2 7168 17407 5.00 MiB nvram
[2020-06-23 12:47:57.462799] 3 17408 37887 10.00 MiB protect1
[2020-06-23 12:47:57.479811] 4 37888 58367 10.00 MiB protect2
[2020-06-23 12:47:57.500102] 5 58368 58879 256.00 KiB seccfg
[2020-06-23 12:47:57.513027] 6 58880 59879 500.00 KiB lk
[2020-06-23 12:47:57.521735] 7 59880 92415 15.89 MiB boot
[2020-06-23 12:47:57.530851] 8 92416 125183 16.00 MiB recovery
[2020-06-23 12:47:57.546480] 9 125184 137471 6.00 MiB secro
[2020-06-23 12:47:57.558800] 10 137472 138495 512.00 KiB para
[2020-06-23 12:47:57.567431] 11 138496 154879 8.00 MiB logo
[2020-06-23 12:47:57.583867] 12 154880 175359 10.00 MiB expdb
[2020-06-23 12:47:57.601516] 13 175360 177407 1024.00 KiB frp
[2020-06-23 12:47:57.612980] 14 177408 187647 5.00 MiB tee1
[2020-06-23 12:47:57.622936] 15 187648 197887 5.00 MiB tee2
[2020-06-23 12:47:57.633490] 16 197888 278527 39.38 MiB metadata
[2020-06-23 12:47:57.647775] 17 278528 280575 1024.00 KiB kb
[2020-06-23 12:47:57.659414] 18 280576 282623 1024.00 KiB dkb
[2020-06-23 12:47:57.679812] 19 282624 3588671 1.58 GiB system
[2020-06-23 12:47:57.690797] 20 3588672 4457023 424.00 MiB cache
[2020-06-23 12:47:57.700665] 21 4457024 4458047 512.00 KiB MISC
[2020-06-23 12:47:57.714175] 22 4458048 4490815 16.00 MiB persisbackup
[2020-06-23 12:47:57.730194] 23 4490816 4499455 4.22 MiB PMT
[2020-06-23 12:47:57.739627] 24 4499456 30325759 12.31 GiB userdata
[2020-06-23 12:47:57.749898] 25 30325760 30551039 110.00 MiB boot_tmp
[2020-06-23 12:47:57.759279] 26 30551040 30776319 110.00 MiB recovery_tmp
[2020-06-23 12:47:58.281302]
[2020-06-23 12:47:58.286574] Writing primary GPT (part 1) to gpt-G000KW0463310950/gpt.bin.step1.gpt
[2020-06-23 12:47:58.428890] Writing backup GPT (part 1) to gpt-G000KW0463310950/gpt.bin.step1.bak
[2020-06-23 12:47:58.455505]
[2020-06-23 12:47:58.466746] Modified GPT Step 2:
[2020-06-23 12:47:58.481602]
[2020-06-23 12:47:58.487415] Sector size (logical): 512 bytes
[2020-06-23 12:47:58.492206] Disk identifier (GUID): 0977B6B6-2B39-4075-8CCF-F0F9A3D117CD
[2020-06-23 12:47:58.511517] Partition table holds up to 128 entries
[2020-06-23 12:47:58.518431] This partition table begins at sector 2 and ends at sector 33
[2020-06-23 12:47:58.523640] First usable sector is 34, last usable sector is 30777310
[2020-06-23 12:47:58.529462] Other partition table is at sector 30777343
[2020-06-23 12:47:58.543548]
[2020-06-23 12:47:58.566847] Number Start (sector) End (sector) Size Name
[2020-06-23 12:47:58.578207] 1 1024 7167 3.00 MiB proinfo
[2020-06-23 12:47:58.600018] 2 7168 17407 5.00 MiB nvram
[2020-06-23 12:47:58.621133] 3 17408 37887 10.00 MiB protect1
[2020-06-23 12:47:58.629613] 4 37888 58367 10.00 MiB protect2
[2020-06-23 12:47:58.642478] 5 58368 58879 256.00 KiB seccfg
[2020-06-23 12:47:58.656863] 6 58880 59879 500.00 KiB lk
[2020-06-23 12:47:58.665863] 7 59880 92415 15.89 MiB boot_x
[2020-06-23 12:47:58.674533] 8 92416 125183 16.00 MiB recovery_x
[2020-06-23 12:47:58.686749] 9 125184 137471 6.00 MiB secro
[2020-06-23 12:47:58.713124] 10 137472 138495 512.00 KiB para
[2020-06-23 12:47:58.726349] 11 138496 154879 8.00 MiB logo
[2020-06-23 12:47:58.738046] 12 154880 175359 10.00 MiB expdb
[2020-06-23 12:47:58.764317] 13 175360 177407 1024.00 KiB frp
[2020-06-23 12:47:58.777031] 14 177408 187647 5.00 MiB tee1
[2020-06-23 12:47:58.793473] 15 187648 197887 5.00 MiB tee2
[2020-06-23 12:47:58.805405] 16 197888 278527 39.38 MiB metadata
[2020-06-23 12:47:58.813721] 17 278528 280575 1024.00 KiB kb
[2020-06-23 12:47:58.823369] 18 280576 282623 1024.00 KiB dkb
[2020-06-23 12:47:58.836732] 19 282624 3588671 1.58 GiB system
[2020-06-23 12:47:58.855238] 20 3588672 4457023 424.00 MiB cache
[2020-06-23 12:47:58.868765] 21 4457024 4458047 512.00 KiB MISC
[2020-06-23 12:47:58.895499] 22 4458048 4490815 16.00 MiB persisbackup
[2020-06-23 12:47:58.905577] 23 4490816 4499455 4.22 MiB PMT
[2020-06-23 12:47:58.913732] 24 4499456 30325759 12.31 GiB userdata
[2020-06-23 12:47:58.925229] 25 30325760 30551039 110.00 MiB boot
[2020-06-23 12:47:58.944759] 26 30551040 30776319 110.00 MiB recovery
[2020-06-23 12:47:59.460926]
[2020-06-23 12:47:59.466811] Writing primary GPT (part 2) to gpt-G000KW0463310950/gpt.bin.step2.gpt
[2020-06-23 12:47:59.594491] Writing backup GPT (part 2) to gpt-G000KW0463310950/gpt.bin.step2.bak

Flashing temp GPT
239 KB/s (17408 bytes in 0.070s)
34+0 records in
34+0 records out
17408 bytes transferred in 0.001 secs (17408000 bytes/sec)

Preparing for Factory Reset

Rebooting into Recovery
x@x:~/Downloads/amonet-giza-t2/amonet$

This seemed to run OK; the device rebooted and did a factory reset. I then ran Step-2. The output is below:

x@x:~/Downloads/amonet-giza-t2/amonet$ sudo ./step-2.sh
Testing root access...
uid=0(root) gid=0(root) context=u:r:init:s0

Looking for partition-suffix
lrwxrwxrwx root root 2020-06-23 11:48 recovery_tmp -> /dev/block/mmcblk0p26

Flashing exploit
57 KB/s (4096 bytes in 0.069s)
3563 KB/s (492132 bytes in 0.134s)
8+0 records in
8+0 records out
4096 bytes transferred in 0.001 secs (4096000 bytes/sec)
961+1 records in
961+1 records out
492132 bytes transferred in 0.035 secs (14060914 bytes/sec)
8+0 records in
8+0 records out
4096 bytes transferred in 0.002 secs (2048000 bytes/sec)
961+1 records in
961+1 records out
492132 bytes transferred in 0.034 secs (14474470 bytes/sec)

Flashing LK
3589 KB/s (487392 bytes in 0.132s)
951+1 records in
951+1 records out
487392 bytes transferred in 0.040 secs (12184800 bytes/sec)

Flashing TZ
3689 KB/s (3307008 bytes in 0.875s)
6459+0 records in
6459+0 records out
3307008 bytes transferred in 0.270 secs (12248177 bytes/sec)
6459+0 records in
6459+0 records out
3307008 bytes transferred in 0.325 secs (10175409 bytes/sec)

Flashing Preloader
44 KB/s (2048 bytes in 0.044s)
44 KB/s (2048 bytes in 0.044s)
1706 KB/s (138924 bytes in 0.079s)
4+0 records in
4+0 records out
2048 bytes transferred in 0.056 secs (36571 bytes/sec)
4+0 records in
4+0 records out
2048 bytes transferred in 0.059 secs (34711 bytes/sec)
271+1 records in
271+1 records out
138924 bytes transferred in 0.067 secs (2073492 bytes/sec)
271+1 records in
271+1 records out
138924 bytes transferred in 0.018 secs (7718000 bytes/sec)

Flashing final GPT
350 KB/s (17408 bytes in 0.048s)
34+0 records in
34+0 records out
17408 bytes transferred in 0.002 secs (8704000 bytes/sec)

Flashing final GPT (backup)
335 KB/s (16896 bytes in 0.049s)
33+0 records in
33+0 records out
16896 bytes transferred in 0.002 secs (8448000 bytes/sec)

Flashing TWRP
3565 KB/s (13512704 bytes in 3.701s)
26392+0 records in
26392+0 records out
13512704 bytes transferred in 1.596 secs (8466606 bytes/sec)

Rebooting into TWRP
x@x:~/Downloads/amonet-giza-t2/amonet$

Unfortunately, after rebooting the device got stuck on the white Amazon logo. I attempted to recover using the original debrick method for douglas (a reworking of the original karnak unlock method) modified for giza: see here (https://xdaforums.com/showpost.php?p=78853205&postcount=1) However the bottom write method fell over; the device failed a gpt check:

x@x:/media/x/SD Card/Giza-Restore/amonet$ sudo ./bootrom-step.sh
[2020-06-23 15:30:19.049767] Waiting for bootrom
[2020-06-23 15:30:33.527575] Found port = /dev/ttyACM0
[2020-06-23 15:30:33.542589] Handshake
[2020-06-23 15:30:33.581694] Disable watchdog

* * * Remove the short and press Enter * * *

[2020-06-23 15:30:35.884990] Init crypto engine
[2020-06-23 15:30:36.034842] Disable caches
[2020-06-23 15:30:36.044648] Disable bootrom range checks
[2020-06-23 15:30:36.161904] Load payload from ../brom-payload/build/payload.bin = 0x4690 bytes
[2020-06-23 15:30:36.205440] Send payload
[2020-06-23 15:30:40.773015] Let's rock
[2020-06-23 15:30:40.788256] Wait for the payload to come online...
[2020-06-23 15:30:41.517972] all good
[2020-06-23 15:30:41.527461] Check GPT
[2020-06-23 15:30:41.888837] gpt_parsed = {'tee1': (177408, 10240), 'boot_x': (59880, 32536), 'nvram': (7168, 10240), 'frp': (175360, 2048), 'metadata': (197888, 80640), 'protect1': (17408, 20480), 'protect2': (37888, 20480), 'logo': (138496, 16384), 'tee2': (187648, 10240), 'secro': (125184, 12288), 'expdb': (154880, 20480), 'seccfg': (58368, 512), 'proinfo': (1024, 6144), 'lk': (58880, 1000), 'recovery_x': (92416, 32768), 'para': (137472, 1024)}
Traceback (most recent call last):
File "main.py", line 123, in <module>
main()
File "main.py", line 69, in main
raise RuntimeError("bad gpt")
RuntimeError: bad gpt
x@x:/media/x/SD Card/Giza-Restore/amonet$

Is there anything I can do to restore this tablet?