[Moto G7 Power Questions & Answers] WoKoschekk:
No, you will only brick your brain, but not your device! :)Although it does not make any sense to do this, I will

try

to explain it:

Regarding to this copy-partions.zip from LineageOS, I'll take my Moto G6+ as an example.

Here is the complete partition layout (mmcblk0):

Number Start (sector) End (sector) Size Code Name

1 256 7423 3.5 MiB A012 xbl_a

2 7424 14591 3.5 MiB FFFF xbl_b

3 14592 18687 2.0 MiB A016 tz_a

4 18688 22783 2.0 MiB FFFF tz_b

5 22784 23807 512.0 KiB A018 rpm_a

6 23808 24831 512.0 KiB FFFF rpm_b

7 24832 25855 512.0 KiB A017 hyp_a

8 25856 26879 512.0 KiB FFFF hyp_b

9 26880 27135 128.0 KiB FFFF devcfg_a

10 27136 27391 128.0 KiB FFFF devcfg_b

11 27392 28415 512.0 KiB A01E pmic_a

12 28416 29439 512.0 KiB FFFF pmic_b

13 29440 31487 1024.0 KiB FFFF abl_a

14 31488 33535 1024.0 KiB FFFF abl_b

15 33536 34559 512.0 KiB FFFF cmnlib_a

16 34560 35583 512.0 KiB FFFF cmnlib64_a

17 35584 36607 512.0 KiB FFFF cmnlib_b

18 36608 37631 512.0 KiB FFFF cmnlib64_b

19 37632 38655 512.0 KiB FFFF keymaster_a

20 38656 39679 512.0 KiB FFFF keymaster_b

21 39680 39935 128.0 KiB FFFF storsec_a

22 39936 40191 128.0 KiB FFFF storsec_b

23 40192 40703 256.0 KiB FFFF prov_a

24 40704 41215 256.0 KiB FFFF prov_b

25 41216 266495 110.0 MiB 0700 modem_a

26 266496 491775 110.0 MiB FFFF modem_b

27 491776 491777 1024 bytes A029 fsc

28 491784 491799 8.0 KiB A02C ssd

29 492032 524799 16.0 MiB FFFF dsp_a

30 524800 557567 16.0 MiB FFFF dsp_b

31 557568 559615 1024.0 KiB A01A ddr

32 559616 560639 512.0 KiB FFFF utags

33 560640 561663 512.0 KiB FFFF utagsBackup

34 561664 565759 2.0 MiB A027 modemst1

35 565760 569855 2.0 MiB A028 modemst2

36 569856 590335 10.0 MiB A02A fsg_a

37 590336 610815 10.0 MiB FFFF fsg_b

38 610816 676351 32.0 MiB A026 persist

39 676352 677375 512.0 KiB FFFF frp

40 677376 677631 128.0 KiB FFFF cid

41 677632 710399 16.0 MiB FFFF carrier

42 710400 711423 512.0 KiB FFFF metadata

43 711424 727807 8.0 MiB FFFF kpan

44 727808 858879 64.0 MiB A036 boot_a

45 858880 989951 64.0 MiB FFFF boot_b

46 989952 1022719 16.0 MiB FFFF dto_a

47 1022720 1055487 16.0 MiB FFFF dto_b

48 1055488 1057535 1024.0 KiB A01F misc

49 1057536 1073919 8.0 MiB FFFF logfs

50 1073920 1074431 256.0 KiB A022 apdp

51 1074432 1074943 256.0 KiB A023 msadp

52 1074944 1074945 1024 bytes A024 dpo

53 1074952 1074959 4.0 KiB A021 devinfo

54 1074960 1084175 4.5 MiB FFFF bluetooth_a

55 1084176 1093391 4.5 MiB FFFF bluetooth_b

56 1093392 1160239 32.6 MiB FFFF logo_a

57 1160240 1227087 32.6 MiB FFFF logo_b

58 1227088 1227215 64.0 KiB FFFF vbmeta_a

59 1227216 1227343 64.0 KiB FFFF vbmeta_b

60 1227344 1261567 16.7 MiB FFFF padA

61 1261568 1277951 8.0 MiB FFFF hw

62 1277952 1294335 8.0 MiB FFFF sp

63 1294336 1785855 240.0 MiB FFFF oem_a

64 1785856 2277375 240.0 MiB FFFF oem_b

65 2277376 4145151 912.0 MiB FFFF vendor_a

66 4145152 6012927 912.0 MiB FFFF vendor_b

67 6012928 11649023 2.7 GiB A038 system_a

68 11649024 17285119 2.7 GiB FFFF system_b

69 17285120 122142686 50.0 GiB A03A userdata

Assuming we start on slot A and slot B is empty.

First of all we should know which partitions are being copied and flashed by the script. Every partition whose name contains a slot will be copied except those:

# Partitions ignored
IGNORED=" dtbo_a dtbo_b system_a system_b boot_a boot_b vbmeta_a vbmeta_b "

Flashing the script will still leave those ones blank, because you will flash them with your ROM. Always.

=> Result of this step: All parts, especially your bootloader, are now copied to slot B. Except the above mentioned "ignored parts"

Now the ignored parts were flashed by the ROM and slot B is completely written (GApps are only single files and not an image for an entire partition, you could ignore them). TWRP installer patches both boot partitions - slot A+B.

=> Result of this step: Slot A is completely written with your old ROM and TWRP. Slot B is completely written with your new ROM and TWRP.

=> Slot A is still the same and Slot B is still the same. Remember the ignored parts!

Reboot sets the active slot to B. So, the ROM will be installed on slot A. TWRP installer patches both slots again.

=> New ROM is installed on both slots now. TWRP was installed a second time = no changes

=> Reboot sets active slot to A and you will boot into your new ROM on slot A.

Any questions? :)