Suggestion to change the DFU name to include part of mac..

I think it's possible that some code actually expects the name DfuTarg so it could be a problematic one to change. Internally the code I use for flashing definitely does.

Which application are you using to do the flashing on iOS?

I know it's frustrating but on Android you wouldn't have the issue. £50 on an Android tablet would fix it for you.

Also it is possible to use https://github.com/thegecko/web-bluetoot­h-dfu which is a Node.js application to flash from a PC (Mac or Linux - Raspberry Pi works too) - so you could set up something like a Raspberry Pi to do the whole flashing process automatically whenever a device named DfuTarg is found