The bootm command does not support uVxWorks image on Cyclone V or Arria 10 board by default,
SOCFPGA_ARRIA10 # bootm 0x100000
Booting kernel from Legacy Image at 00100000 …
Image Name: vxworks
Image Type: ARM VxWorks Kernel Image (uncompressed)
Data Size: 2453112 Bytes = 2.3 MiB
Load Address: 00100000
Entry Point: 00100000
Verifying Checksum … OK
Loading Kernel Image … OK
ERROR: booting os ‘VxWorks’ (14) is not supported