[OnePlus 6T  Questions & Answers] mudlee:
Hi Everyone!

I tried to install LineageOS to my OP based on the OP6T page at the LineageOS website (I cannot link as it's my first post). I did everything as it was written without errors and after the last reboot nothing happened, I got back my Oxygen OS with google. I thought I might screwed up something, so I started it over again. At step "Installing LineageOS from recovery / step 5" when they say "Return to the previous menu" I had two options as first time.

1: tapping back until I really get back

2: reboot

First time I chose the first one, so I thought I might reboot now instead. Then I got no TWRP again back. After many-many tries, currently I'm at a point where I can access fastboot. My plan is to get back the original Oxygen OS and try again installing LineageOS.

The problem I face with can see in the end of the post.

I used adb/fastboot downloaded from google and I downloaded the latest OTA software from oneplus itself. After booting the phone, I see the OP loading logo stuck. I can get into fastboot by holding down all buttons (to halt the phone) and then turning it off with holding POWER+VOL DOWN. Then I get into a blueish menu (not fastboot or twrp!) where I can reboot into recovery/fastboot or wipe data.

Note, that the images.zip is created by me by extracting the payload.bin from the OTA zip I downloaded from OP's site.

I also tried to install back TWRP by flashing it onto boot, but the phone got again into an andless loading screen.

Yes, I know we have a tool called MSM, but I have no windows available, only linux and macos. I tried wine and virtualbox running windows but MSM didn't recognize my phone.

Any idea what can I do?

Logs:

mudlee@zerg:~/Downloads/ota/output$ ./fastboot update images.zip
--------------------------------------------
Bootloader Version...:
Baseband Version.....:
Serial Number........: e5a9f9c
--------------------------------------------
extracting android-info.txt (0 MB) to RAM...
Checking 'product' OKAY [ 0.001s]
Setting current slot to 'a' OKAY [ 0.007s]
extracting boot.img (64 MB) to disk... took 0.187s
archive does not contain 'boot.sig'
Sending 'boot_a' (65536 KB) OKAY [ 2.032s]
Writing 'boot_a' OKAY [ 0.333s]
extracting dtbo.img (8 MB) to disk... took 0.051s
archive does not contain 'dtbo.sig'
Sending 'dtbo' (8192 KB) OKAY [ 0.250s]
Writing 'dtbo' OKAY [ 0.052s]
archive does not contain 'dt.img'
archive does not contain 'recovery.img'
extracting vbmeta.img (0 MB) to disk... took 0.000s
archive does not contain 'vbmeta.sig'
Sending 'vbmeta' (8 KB) OKAY [ 0.003s]
Writing 'vbmeta' OKAY [ 0.001s]
archive does not contain 'vbmeta_system.img'
archive does not contain 'vendor_boot.img'
archive does not contain 'super_empty.img'
archive does not contain 'boot_other.img'
archive does not contain 'odm.img'
archive does not contain 'product.img'
extracting system.img (2860 MB) to disk... took 12.379s
Invalid sparse file format at header magic
archive does not contain 'system.sig'
Sending sparse 'system_a' 1/6 (513608 KB) OKAY [ 16.216s]
Writing 'system_a' OKAY [ 0.001s]
Sending sparse 'system_a' 2/6 (514145 KB) OKAY [ 18.289s]
Writing 'system_a' OKAY [ 0.001s]
Sending sparse 'system_a' 3/6 (515013 KB) OKAY [ 18.389s]
Writing 'system_a' OKAY [ 0.001s]
Sending sparse 'system_a' 4/6 (515534 KB) OKAY [ 18.281s]
Writing 'system_a' OKAY [ 0.001s]
Sending sparse 'system_a' 5/6 (510919 KB) OKAY [ 18.317s]
Writing 'system_a' OKAY [ 0.001s]
Sending sparse 'system_a' 6/6 (184768 KB) OKAY [ 8.139s]
Writing 'system_a' OKAY [ 0.001s]
archive does not contain 'system_ext.img'
archive does not contain 'system_other.img'
extracting vendor.img (1024 MB) to disk... took 4.095s
Invalid sparse file format at header magic
archive does not contain 'vendor.sig'
Sending sparse 'vendor' 1/2 (511135 KB) OKAY [ 16.211s]
Writing 'vendor' OKAY [ 0.001s]
Sending sparse 'vendor' 2/2 (389097 KB) OKAY [ 15.169s]
Writing 'vendor' OKAY [ 0.001s]
archive does not contain 'vendor_other.img'
Rebooting OKAY [ 10.729s]
Finished. Total time: 165.761s