Help/Support Modded binary immediately closes app?

[al3xs7x 3 iPhone SE (2020) 14.3]

Hey, here's my typical app modding workflow:

1. Decrypt .ipa using bfdecrypt (only decryption tool that works on Taurine 14.3, as far as i have found)
2. Extract binary from new decrypted .ipa
3. Thin it using lipo (only if it's multi arch binary)
4. Fix permissions to 755/777
5. Throw it in GHIDRA and start analyzing
6. Manually apply mods/patches to binary using hex editor, and directly replace original one in app's bundle

Now, for some reason, this game https://apps.apple.com/us/app/id938586035 immediately closes after modding. Actually, even without modding, after only first two steps, if i replace original binary with decrypted one, it refuses to start. Does anyone have an idea what it could be, it's a random free game, and i don't think it has to do something with some form of anti-piracy..

Updated September 9, 2021 by al3xs7x

[Laxus 808k iPhone 5s 10.3.3]

Use CrackerXI+ from iphonecake instead. No longer required lipo and manual setting permission

[al3xs7x 3 iPhone SE (2020) 14.3]

I know, but it doesn't work on libhooker (Taurine). So you think it's bfdecrypt's fault?

[Rook 559.3k iPad Pro (2nd gen) 17.4 Donor]

I can’t fully remember, but you may need AppSync installed and try running ldid -S on the binary.

[Laxus 808k iPhone 5s 10.3.3]

39 minutes ago, al3xs7x said:

I know, but it doesn't work on libhooker (Taurine). So you think it's bfdecrypt's fault?

You need to fakesign the binary with ldid if using bfdecrypt

[0xSUBZ3R0 134.7k iPhone 6s Plus 12.1.1]

39 minutes ago, Laxus said:

You need to fakesign the binary with ldid if using bfdecrypt

use sidelodly ?

[al3xs7x 3 iPhone SE (2020) 14.3]

52 minutes ago, Rook said:

I can’t fully remember, but you may need AppSync installed and try running ldid -S on the binary.

 

51 minutes ago, Laxus said:

You need to fakesign the binary with ldid if using bfdecrypt

 

Yes, i have AppSync Unified installed. I have never used ldid, do i use it on phone or pc?

Updated September 9, 2021 by al3xs7x

[Rook 559.3k iPad Pro (2nd gen) 17.4 Donor]

2 minutes ago, al3xs7x said:

 

 

Yes, i have AppSync Unified installed. I have never used ldid, do i use it on phone or pc?

Device. Install Link Identity Editor from Cydia.

[al3xs7x 3 iPhone SE (2020) 14.3]

ldid -S did the trick! Thanks! Is the sign universal, eg. will it work on other devices? I am planning to release some patches/mods, is ipa the best way, i guess releasing only patched binary and requiring of users to replace original one in bundle is stupid..?

Updated September 9, 2021 by al3xs7x

[Rook 559.3k iPad Pro (2nd gen) 17.4 Donor]

1 hour ago, al3xs7x said:

ldid -S did the trick! Thanks! Is the sign universal, eg. will it work on other devices? I am planning to release some patches/mods, is ipa the best way, i guess releasing only patched binary and requiring of users to replace original one in bundle is stupid..?

I really don't remember. Binary modifications are a thing of the past, and we don't approve those anymore, unless you release as IPA. Then Sideloadly will take care of the signing.