NetInstall fails when downloading kernelcache

When trying to boot a NetInstall or NetRestore image over the network all works fine until the client tries to download the

file. At block 3005, the client keeps sending ACKs for block 3004 (s. screenshot). **Edit:** There seem to be some problems loading the image, so here's a rough transcription: Server -> Client: Data Packet, Block 3004 Client -> Server: Acknowledgement, Block 3004 Server -> Client: Data Packet, Block 3005 Client -> Server: Acknowledgement, Block 3004 Server -> Client: Data Packet, Block 3005 Client -> Server: Acknowledgement, Block 3004 Server -> Client: Data Packet, Block 3005 Client -> Server: Acknowledgement, Block 3004 The kernelcache file is below the (old) magic threshold of 32M. Server: - macOS 10.12.4 - Server 5.3 Client: - macOS 10.12.3 (if that matters at all) - MacBookPro12,1 (so nothing outdated)