ERROR: Failed to download ISP

[sourcelocation]

Tried running PyBoot about 15 times on my iPhone 7 (iphone9,3), iOS 13.5.1 is the version of main OS, and ios 11.4.1 is the second. Log:

iMac-Matthew:PyBoot-master imac$ ./pyboot.py -i iPhone9,3 11.4.1 -d disk0s1s6
PyBoot - A tool for tether booting Checkm8 vulnerable iOS devices by Matty, @mosk_i

Current version is: Beta 0.8
User choose to boot 11.4.1 from /dev/disk0s1s6.
Make sure your device is connected in DFU mode
1
Checking theiphonewiki for 11.4.1 keys...
Found Keys!
Downloading 11.4.1's BuildManifest.plist
Extracting: BuildManifest.plist, from iPhone_4.7_P3_11.0_11.4.1_15G77_Restore.ipsw
Found multiple device models...
Which is your device?

1: d101ap
2: d10ap
3: d201ap
4: d20ap

Enter the number that corresponds with your device: Device set to d101ap
Getting SHSH for signing images
Downloading and patching 11.4.1's iBSS/iBEC
Extracting: Firmware/dfu/iBEC.d10.RELEASE.im4p, from iPhone_4.7_P3_11.0_11.4.1_15G77_Restore.ipsw
Extracting: Firmware/dfu/iBSS.d10.RELEASE.im4p, from iPhone_4.7_P3_11.0_11.4.1_15G77_Restore.ipsw
dyld: Library not loaded: /usr/local/lib/libpng16.16.dylib
  Referenced from: /Users/imac/Downloads/PyBoot-master/./resources/bin/ibootim
  Reason: image not found
Downloading 11.4.1's KernelCache
Extracting: kernelcache.release.iphone9, from iPhone_4.7_P3_11.0_11.4.1_15G77_Restore.ipsw
Downloading 11.4.1's DeviceTree
Extracting: Firmware/all_flash/DeviceTree.d101ap.im4p, from iPhone_4.7_P3_11.0_11.4.1_15G77_Restore.ipsw
iOS version is 11.x, not downloading trustcache
Downloading 11.4.1's AOPFW
Extracting: Firmware/AOP/aopfw-t8010aop.im4p, from iPhone_4.7_P3_11.0_11.4.1_15G77_Restore.ipsw
Downloading 11.4.1's ISP
Extracting: Firmware/isp_bni/, from iPhone_4.7_P3_11.0_11.4.1_15G77_Restore.ipsw
ERROR: Failed to download ISP
Please re-run PyBoot again and it should work (might take a few tries)

[DangerousPixel]

same here