[Asus Zenfone 9] reyqn:
So I have the same issue with my 100 firmware. I guess I could flash 142 and then update with OTAs to 34.0304.2004.75, but if we can't use OTAs without flashing a full firmware image before, we're stuck until Asus decides to upload a new one aren't we?

I tried to unroot manually by flashing a stock boot.img, but I still couldn't use the OTA...

02-08 23:39:41.748 1930 1930 E update_engine: [ERROR:verified_source_fd.cc(50)] Unable to open ECC source partition /dev/block/bootdevice/by-name/boot_b: No such file or directory (2)
02-08 23:39:41.749 1930 1930 E update_engine: [ERROR:partition_writer.cc(317)] The hash of the source data on disk for this operation doesn't match the expected value. This could mean that the delta update payload was targeted for another version, or that the source partition was modified after it was installed, for example, by mounting a filesystem.
02-08 23:39:41.750 1930 1930 E update_engine: [ERROR:partition_writer.cc(322)] Expected: sha256|hex = DBCFDAFC37D395411111ADEC697E3C3EC9783FDAA394855E998974382582C92C
02-08 23:39:41.751 1930 1930 E update_engine: [ERROR:partition_writer.cc(325)] Calculated: sha256|hex = 23CC0A4122E1CDB6CEC4A25D18F56ED8B7556F4F0A6C686E5C2125C096049DAD
02-08 23:39:41.752 1930 1930 E update_engine: [ERROR:partition_writer.cc(336)] Operation source (offset:size) in blocks: 0:1,11740:1,24575:1
02-08 23:39:41.753 1930 1930 E update_engine: [ERROR:partition_writer.cc(261)] source_fd != nullptr failed.
02-08 23:39:41.754 1930 1930 E update_engine: [ERROR:delta_performer.cc(1231)] partition_writer_->PerformDiffOperation( operation, error, buffer_.data(), buffer_.size()) failed.
02-08 23:39:41.755 1930 1930 E update_engine: [ERROR:delta_performer.cc(209)] Failed to perform BROTLI_BSDIFF operation 56, which is the operation 0 in partition "boot"
02-08 23:39:41.756 1930 1930 E update_engine: [ERROR:download_action.cc(227)] Error ErrorCode::kDownloadStateInitializationError (20) in DeltaPerformer's Write method when processing the received payload -- Terminating processing
02-08 23:39:41.758 1930 1930 I update_engine: [INFO:delta_performer.cc(225)] Discarding 201 unused downloaded bytes
02-08 23:39:41.801 1930 1930 I update_engine: [INFO:multi_range_http_fetcher.cc(177)] Received transfer terminated.
02-08 23:39:41.803 1930 1930 I update_engine: [INFO:multi_range_http_fetcher.cc(129)] TransferEnded w/ code 200
02-08 23:39:41.804 1930 1930 I update_engine: [INFO:multi_range_http_fetcher.cc(131)] Terminating.
02-08 23:39:41.805 1930 1930 I update_engine: [INFO:action_processor.cc(116)] ActionProcessor: finished DownloadAction with code ErrorCode::kDownloadStateInitializationError
02-08 23:39:41.806 1930 1930 I update_engine: [INFO:action_processor.cc(121)] ActionProcessor: Aborting processing due to failure.
02-08 23:39:41.807 1930 1930 I update_engine: [INFO:update_attempter_android.cc(565)] Processing Done.
02-08 23:39:41.809 1930 1930 I update_engine: [INFO:delta_performer.cc(1670)] Resetting recorded hash for prepared partitions.
02-08 23:39:41.810 1930 1930 I update_engine: [INFO:update_attempter_android.cc(592)] Resetting update progress.
02-08 23:39:41.871 1930 1930 I update_engine: Successfully unmapped snapshot odm_a
02-08 23:39:41.935 1930 1930 I update_engine: Successfully unmapped snapshot vendor_a
02-08 23:39:42.003 1930 1930 I update_engine: Successfully unmapped snapshot product_a
02-08 23:39:42.083 1930 1930 I update_engine: Successfully unmapped snapshot system_ext_a
02-08 23:39:42.155 1930 1930 I update_engine: Successfully unmapped snapshot vendor_dlkm_a
02-08 23:39:42.255 1930 1930 I update_engine: Successfully unmapped snapshot system_a
02-08 23:39:42.257 1930 1930 I update_engine: [INFO:dynamic_partition_control_android.cc(305)] Destroying [odm_a, product_a, system_a, system_ext_a, vendor_a, vendor_dlkm_a] from device mapper
02-08 23:39:42.271 1930 1930 I update_engine: [INFO:metrics_reporter_android.cc(159)] Current update attempt downloads 0 bytes data