I also have an iPhone 6 that I have updated iOS to 12.3. I can get the B4x-Bridge app to start installing, but it stops half way through and won't complete the install. I have your ca.pem certificate installed and it is 'Trusted'. Any thoughts of why it won't complete the install on an iPhone 6 running iOS 12.3?
>Try to restart the device. And try to change the package name.
I did the above but no change. Well, I'm out of idea's. I tried 32bit and 64bit as well. I guess I'm at a dead end. I can't use my iPhone 4 or iPhone 6. I'll try to find an iPhone 7 now.
I re-checked my iphone 6 UDID string. I have it in my Devices file in my Apple development account. My ad_hoc.mobileprovision file includes the iphone6. I -regenerated the ad_hoc file and copied it into my keys folder.
The install starts...I see the grayed out icon, the sweeping 'radar' circle (install progress indicator) starts to move around its clock face and at about the 6 o'clock position, the install just stops. The bridge icon remains on the iPhone 6 desktop but in a grayed out state.