[OnePlus 7T Guides, News, & Discussion] anak1n:
I tried to flash fastboot rom, coming from A11 beta (already done it successfully once) but now phone`s stuck in boot screen (circling dots).

Here`s output from flash:

Do you want to wipe all the data ( Reccomended )[Y/N]?y

Erasing 'userdata' OKAY [ 0.133s]

F2FS-tools: mkfs.f2fs Ver: 1.12.0 (2018-11-12)

Info: Disable heap-based policy

Info: Debug level = 1

Info: Trim is disabled

Info: Set conf for android

Info: Segments per section = 1

Info: Sections per zone = 1

Info: sector size = 512

Info: total sectors = 203951144 (99585 MB)

Info: zone aligned segment0 blkaddr: 512

Info: add quota type = 0 => 4

Info: add quota type = 1 => 5

[f2fs_init_sit_area: 535] Filling sit area at offset 0x00600000

[f2fs_init_nat_area: 569] Filling nat area at offset 0x00e00000

[f2fs_write_root_inode:1147] Writing root inode (hot node), 1ba00 0 200 at offset 0x00113152

[f2fs_write_default_quota:1223] Writing quota data, at offset 0001c001, 0001c002

[f2fs_write_qf_inode:1318] Writing quota inode (hot node), 1ba00 0 200 at offset 0x00113153

[f2fs_write_default_quota:1223] Writing quota data, at offset 0001c003, 0001c004

[f2fs_write_qf_inode:1318] Writing quota inode (hot node), 1ba00 0 200 at offset 0x00113154

[f2fs_update_nat_root:1372] Writing nat root, at offset 0x00000e00

[f2fs_add_default_dentry_root:1567] Writing default dentry root, at offset 0x0001c000

Info: Overprovision ratio = 0.640%

Info: Overprovision segments = 635 (GC reserved = 320)

[f2fs_write_check_point_pack: 713] Writing main segments, cp at offset 0x00000200

[f2fs_write_check_point_pack: 850] Writing Segment summary for HOT/WARM/COLD_DATA, at offset 0x00000201

[f2fs_write_check_point_pack: 877] Writing Segment summary for HOT_NODE, at offset 0x00000202

[f2fs_write_check_point_pack: 889] Writing Segment summary for WARM_NODE, at offset 0x00000203

[f2fs_write_check_point_pack: 900] Writing Segment summary for COLD_NODE, at offset 0x00000204

[f2fs_write_check_point_pack: 908] Writing cp page2, at offset 0x00000205

[f2fs_write_check_point_pack: 928] Writing NAT bits pages, at offset 0x000003fe

[f2fs_write_check_point_pack: 949] Writing cp page 1 of checkpoint pack 2, at offset 0x00000400

[f2fs_write_check_point_pack: 968] Writing cp page 2 of checkpoint pack 2, at offset 0x00000405

[f2fs_write_super_block:1001] Writing super block, at offset 0x00000000

Info: format successful

Sending 'userdata' (85 KB) OKAY [ 0.011s]

Writing 'userdata' OKAY [ 0.004s]

Erasing 'metadata' OKAY [ 0.006s]

Erase successful, but not automatically formatting.

File system type raw not supported.

Finished. Total time: 8.116s

Sending 'boot_a' (98304 KB) OKAY [ 3.057s]

Writing 'boot_a' OKAY [ 0.463s]

Finished. Total time: 3.686s

Sending 'dtbo' (16384 KB) OKAY [ 0.498s]

Writing 'dtbo' OKAY [ 0.058s]

Finished. Total time: 0.599s

Sending 'modem_a' (165396 KB) OKAY [ 5.216s]

Writing 'modem_a' OKAY [ 0.808s]

Finished. Total time: 6.283s

Sending 'reserve' (250164 KB) OKAY [ 7.444s]

Writing 'reserve' FAILED (remote: '(reserve_a) No such partition')

fastboot: error: Command failed

Sending 'recovery' (98304 KB) OKAY [ 3.015s]

Writing 'recovery' OKAY [ 0.394s]

Finished. Total time: 3.572s

Sending 'vbmeta' (8 KB) OKAY [ 0.016s]

Writing 'vbmeta' OKAY [ 0.000s]

Finished. Total time: 0.031s

Sending 'vbmeta_system' (4 KB) OKAY [ 0.013s]

Writing 'vbmeta_system' OKAY [ 0.003s]

Finished. Total time: 0.037s

Rebooting into fastboot OKAY [ 0.003s]

< waiting for any device >

Finished. Total time: 8.464s

Sending 'abl_a' (1164 KB) OKAY [ 0.034s]

Writing 'abl_a' OKAY [ 0.012s]

Finished. Total time: 0.060s

Sending 'aop_a' (200 KB) OKAY [ 0.005s]

Writing 'aop_a' OKAY [ 0.006s]

Finished. Total time: 0.021s

Sending 'bluetooth_a' (828 KB) OKAY [ 0.023s]

Writing 'bluetooth_a' OKAY [ 0.010s]

Finished. Total time: 0.045s

Sending 'cmnlib_a' (384 KB) OKAY [ 0.012s]

Writing 'cmnlib_a' OKAY [ 0.008s]

Finished. Total time: 0.029s

Sending 'cmnlib64_a' (500 KB) OKAY [ 0.015s]

Writing 'cmnlib64_a' OKAY [ 0.009s]

Finished. Total time: 0.035s

Sending 'devcfg_a' (52 KB) OKAY [ 0.002s]

Writing 'devcfg_a' OKAY [ 0.005s]

Finished. Total time: 0.016s

Sending 'dsp_a' (65536 KB) OKAY [ 1.906s]

Writing 'dsp_a' OKAY [ 0.364s]

Finished. Total time: 2.366s

Sending 'hyp_a' (480 KB) OKAY [ 0.014s]

Writing 'hyp_a' OKAY [ 0.007s]

Finished. Total time: 0.030s

Sending 'imagefv_a' (20 KB) OKAY [ 0.002s]

Writing 'imagefv_a' OKAY [ 0.006s]

Finished. Total time: 0.016s

Sending 'keymaster_a' (248 KB) OKAY [ 0.008s]

Writing 'keymaster_a' OKAY [ 0.004s]

Finished. Total time: 0.021s

Sending 'LOGO_a' (6540 KB) OKAY [ 0.187s]

Writing 'LOGO_a' OKAY [ 0.046s]

Finished. Total time: 0.260s

Sending 'multiimgoem_a' (16 KB) OKAY [ 0.002s]

Writing 'multiimgoem_a' OKAY [ 0.005s]

Finished. Total time: 0.015s

Resizing 'odm_a' OKAY [ 0.005s]

Sending 'odm_a' (912 KB) OKAY [ 0.027s]

Writing 'odm_a' OKAY [ 0.290s]

Finished. Total time: 0.337s

Sending 'oem_stanvbk' (2480 KB) OKAY [ 0.073s]

Writing 'oem_stanvbk' OKAY [ 0.021s]

Finished. Total time: 0.108s

Invalid sparse file format at header magic

Sending sparse 'opproduct_a' 1/1 (391808 KB) OKAY [ 11.729s]

Writing 'opproduct_a' OKAY [ 3.135s]

Finished. Total time: 16.970s

Sending 'qupfw_a' (72 KB) OKAY [ 0.003s]

Writing 'qupfw_a' OKAY [ 0.003s]

Finished. Total time: 0.014s

Sending 'storsec_a' (24 KB) OKAY [ 0.002s]

Writing 'storsec_a' OKAY [ 0.002s]

Finished. Total time: 0.011s

Sending 'tz_a' (3092 KB) OKAY [ 0.087s]

Writing 'tz_a' OKAY [ 0.025s]

Finished. Total time: 0.126s

Sending 'uefisecapp_a' (124 KB) OKAY [ 0.005s]

Writing 'uefisecapp_a' OKAY [ 0.006s]

Finished. Total time: 0.018s

Sending 'xbl_a' (3120 KB) OKAY [ 0.092s]

Writing 'xbl_a' OKAY [ 0.060s]

Finished. Total time: 0.164s

Sending 'xbl_config_a' (124 KB) OKAY [ 0.005s]

Writing 'xbl_config_a' OKAY [ 0.009s]

Finished. Total time: 0.023s

Invalid sparse file format at header magic

Resizing 'system_a' OKAY [ 0.005s]

Sending sparse 'system_a' 1/5 (523136 KB) OKAY [ 15.775s]

Writing 'system_a' OKAY [ 3.090s]

Sending sparse 'system_a' 2/5 (523148 KB) OKAY [ 17.110s]

Writing 'system_a' OKAY [ 3.083s]

Sending sparse 'system_a' 3/5 (523640 KB) OKAY [ 16.699s]

Writing 'system_a' OKAY [ 3.065s]

Sending sparse 'system_a' 4/5 (524256 KB) OKAY [ 15.764s]

Writing 'system_a' OKAY [ 3.060s]

Sending sparse 'system_a' 5/5 (198084 KB) OKAY [ 5.717s]

Writing 'system_a' OKAY [ 1.365s]

Finished. Total time: 94.105s

Invalid sparse file format at header magic

Resizing 'vendor_a' OKAY [ 0.005s]

Sending sparse 'vendor_a' 1/2 (523681 KB) OKAY [ 15.290s]

Writing 'vendor_a' OKAY [ 3.071s]

Sending sparse 'vendor_a' 2/2 (427880 KB) OKAY [ 12.903s]

Writing 'vendor_a' OKAY [ 2.563s]

Finished. Total time: 37.628s

Invalid sparse file format at header magic

Resizing 'product_a' OKAY [ 0.005s]

Sending sparse 'product_a' 1/3 (523616 KB) OKAY [ 15.703s]

Writing 'product_a' OKAY [ 3.070s]

Sending sparse 'product_a' 2/3 (523628 KB) OKAY [ 16.698s]

Writing 'product_a' OKAY [ 3.076s]

Sending sparse 'product_a' 3/3 (245308 KB) OKAY [ 7.641s]

Writing 'product_a' OKAY [ 1.603s]

Finished. Total time: 53.314s

Rebooting OKAY [ 0.001s]

Finished. Total time: 0.002s

Press any key to continue . . .

I`m downloading rollback packaga from A11b to A10b to try that first and afterwards back to stable..