Problems installing Lineage OS 14.1 on Lenovo P2 (black screen/blue LED)
OK, fixed - in the end I did this:

Tried "flashback" to stock android 6 with this zip file.

That didn't just work, so I tried with the automated script "flashall" in the zip.

That failed for the partition/image prov/prov32.mbn with the error message:
FAILED (remote: Do not allow to flash Bootloader image on Unlock device)

I then went into the 
PRODUCT_CONFIGURATION_KUNTAO_ROW.xml file and looked at the command list.

I then executed all remaining steps except the ones to delete partitions, for instance

&lt;KUNTAO_ROW_IFLASH&gt;
...
&lt;step operation="flash" filename="prov32.mbn" partition="prov"/&gt;
(first failure in script)

&lt;step operation="flash" filename="sbl1.mbn" partition="sbl1"/&gt;


became


  fastboot flash sbl1 sbl1.mbn (failed with same error)


&lt;step operation="flash" filename="sbl1.mbn" partition="sbl1bak"/&gt;


became


  fastboot flash sbl1bak sbl1.mbn (worked)


and so on all the way through, but skipping the instructions to erase (although I would have done it if the phone didn't start up). It did and I now have ROW (Rest Of World or normal) firmware rather than a carrier-specific version blocking OTA updates due to compatibility with one of their own apps.

I could then pick up a series of normal OTA updates from Lenovo, including Android 7, so I now don't need Lineage OS to get an upgrade for this device (at least not before they do an official Android 8 ROM for it :) ).

&lt;step operation="flash" filename="rpm.mbn" partition="rpm"/&gt; - didn't work
&lt;step operation="flash" filename="rpm.mbn" partition="rpmbak"/&gt;
&lt;step operation="flash" filename="devcfg.mbn" partition="devcfg"/&gt; - didn't work
&lt;step operation="flash" filename="devcfg.mbn" partition="devcfgbak"/&gt;
&lt;step operation="flash" filename="lksecapp.mbn" partition="lksecapp"/&gt;
&lt;step operation="flash" filename="lksecapp.mbn" partition="lksecappbak"/&gt;
&lt;step operation="flash" filename="tz.mbn" partition="tz"/&gt; - didn't work
&lt;step operation="flash" filename="tz.mbn" partition="tzbak"/&gt;
&lt;step operation="flash" filename="keymaster.mbn" partition="keymaster"/&gt; - didn't work
&lt;step operation="flash" filename="cmnlib.mbn" partition="cmnlib"/&gt; - didn't work
&lt;step operation="flash" filename="cmnlib.mbn" partition="cmnlibbak"/&gt;
&lt;step operation="flash" filename="cmnlib64.mbn" partition="cmnlib64"/&gt; - didn't work
&lt;step operation="flash" filename="cmnlib64.mbn" partition="cmnlib64bak"/&gt;
&lt;step operation="flash" filename="emmc_appsboot.mbn" partition="aboot"/&gt; - didn't work
&lt;step operation="flash" filename="emmc_appsboot.mbn" partition="abootbak"/&gt;
&lt;step operation="flash" filename="logo.bin" partition="logo"/&gt;
&lt;step operation="flash" filename="NON-HLOS.bin" partition="modem"/&gt; - didn't work
&lt;step operation="flash" filename="fsg.mbn" partition="fsg"/&gt;
&lt;step operation="erase" partition="modemst1"/&gt; - skipped
&lt;step operation="erase" partition="modemst2"/&gt; - skipped
&lt;step operation="flash" filename="adspso.bin" partition="dsp"/&gt;
&lt;step operation="flash" filename="boot.img" partition="boot"/&gt;
&lt;step operation="flash" filename="recovery.img" partition="recovery"/&gt;
&lt;step operation="flash" filename="systemchunk0.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk1.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk2.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk3.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk4.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk5.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk6.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk7.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk8.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk9.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk10.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk11.img" partition="system"/&gt;
&lt;step operation="flash" filename="systemchunk12.img" partition="system"/&gt;
&lt;step operation="flash" filename="cache.img" partition="cache"/&gt;
&lt;step operation="erase" partition="userdata"/&gt; - skipped
&lt;step var="config bootmode factory" operation="oem"/&gt; - skipped


EDIT: On the plus side, I just got the newly released Lineage 15.1 ROM to work for this phone.