[CosmoJay]

hi
so i have a Lenovo K8 plus 3 GB ram variant. Let me explain what happened first. 
I unlocked my device's bootloader to flash the patched boot image for magisk root, then this orange state sign started showing up everytime i booted up. then when the latest update rolled out in march, i decided to relock the bootloader and then update my device. I re-locked and then a red state sign showing up accompanied by bootloop (it said something like rollback kernel too). so I formatted the whole thing(I used format all option) via Sp Flash Tool and downloaded the stock rom.
now when i try to flash it, pre-loader flashes FINE, recovery flashes FINE, but when it comes to md1img it shows this error: STATUS_INSUFFICIENT_BUFFER (0xC0010007). I tried flashing all the files individually to find the cause of the problem and see exactly which particular flash file was causing the problem. results are as follows.
[STATUS_INSUFFICIENT_BUFFER (0xC0010007) ]- this error was displayed while flashing these files - md1img, md1dsp, md1arm7, md3img.
[ STATUS_SEC_IMG_TOO_LARGE (0xC0020005)] - only popped up while flashing the oem image.
when I exclude these files from the queue, the rest files flash fine. 

Then, I tried to flash the stock ROM using adb (flash-all script). it says "FAILED (remote: not allowed in locked state). Now I cant unlock the bootloader (Tried but failed) since I cant toggle the "allow OEM unlocking" from the fastboot menu. 
Please, help me.
Thanks in advance

[hovatek]

hi
so i have a Lenovo K8 plus 3 GB ram variant. Let me explain what happened first.
I unlocked my device's bootloader to flash the patched boot image for magisk root, then this orange state sign started showing up everytime i booted up. then when the latest update rolled out in march, i decided to relock the bootloader and then update my device. I re-locked and then a red state sign showing up accompanied by bootloop (it said something like rollback kernel too). so I formatted the whole thing(I used format all option) via Sp Flash Tool and downloaded the stock rom.
now when i try to flash it, pre-loader flashes FINE, recovery flashes FINE, but when it comes to md1img it shows this error: STATUS_INSUFFICIENT_BUFFER (0xC0010007). I tried flashing all the files individually to find the cause of the problem and see exactly which particular flash file was causing the problem. results are as follows.
[STATUS_INSUFFICIENT_BUFFER (0xC0010007) ]- this error was displayed while flashing these files - md1img, md1dsp, md1arm7, md3img.
[ STATUS_SEC_IMG_TOO_LARGE (0xC0020005)] - only popped up while flashing the oem image.
when I exclude these files from the queue, the rest files flash fine.

Then, I tried to flash the stock ROM using adb (flash-all script). it says "FAILED (remote: not allowed in locked state). Now I cant unlock the bootloader (Tried but failed) since I cant toggle the "allow OEM unlocking" from the fastboot menu.
Please, help me.
Thanks in advance

You might be getting this because the phone has an invalid IMEI or Baseband. What's the current state of the phone (stuck at logo / bootloop).
How many different stock roms for your model have you tried?