vbmeta patching script does not correctly read the current slot

[ilya980]

Hi,

I am getting an error trying to patch vbmeta. It looks like the 'slot' variable in mtk_da_handler.py is not read correctly. Do you know what is wrong? The phone is LG K40, MT 6765, bootloader is unlocked, has 2 slots: "a" and "b". Thanks!

kali㉿kali)-[~/mtkclient]
└─$ python mtk.py da vbmeta 3
MTK Flash/Exploit Client Public V2.0.1 (c) B.Kerler 2018-2024

DAXFlash - HW-CODE : 0x766
DAXFlash - HWSUB-CODE : 0x8A00
DAXFlash - HW-VERSION : 0xCA00
DAXFlash - SW-VERSION : 0x0
DAXFlash - CHIP-EVOLUTION : 0x0
DAXFlash - DA-VERSION : 1.0
Traceback (most recent call last):
File "/home/kali/mtkclient/mtk.py", line 1021, in
main()
File "/home/kali/mtkclient/mtk.py", line 1017, in main
mtk = Main(args).run(parser)
^^^^^^^^^^^^^^^^^^^^^^
File "/home/kali/mtkclient/mtkclient/Library/mtk_main.py", line 684, in run
da_handler.handle_da_cmds(mtk, cmd, self.args)
File "/home/kali/mtkclient/mtkclient/Library/DA/mtk_da_handler.py", line 942, in handle_da_cmds
self.da_vbmeta(vbmode=vbmode)
File "/home/kali/mtkclient/mtkclient/Library/DA/mtk_da_handler.py", line 188, in da_vbmeta
slot = self.get_current_slot()
^^^^^^^^^^^^^^^^^^^^^^^
File "/home/kali/mtkclient/mtkclient/Library/DA/mtk_da_handler.py", line 679, in get_current_slot
slot = tmp[0x800:0x802].decode('utf-8')
~~~^^^^^^^^^^^^^
TypeError: 'NoneType' object is not subscriptable