ERROR: [Labtools 27-3165] End of startup status: LOW when [ run --target=nexys_a7 --flag=cpu_el2 swervolf]

With EH1 it works but after changed to EL2, it failed with the following errors.
Please let me know your advice.

NFO: Programming part xc7a100tcsg324-1 with bitstream swervolf_0.7.3.bit
INFO: [Labtools 27-2285] Connecting to hw_server url TCP:localhost:3121
INFO: [Labtools 27-2222] Launching hw_server...
INFO: [Labtools 27-2221] Launch Output:

****** Xilinx hw_server v2018.3
**** Build date : Dec 6 2018-23:53:53
** Copyright 1986-2018 Xilinx, Inc. All Rights Reserved.

INFO: Trying to use hardware target localhost:3121/xilinx_tcf/Digilent/210292AA7B77A
INFO: [Labtoolstcl 44-466] Opening hw_target localhost:3121/xilinx_tcf/Digilent/210292AA7B77A
INFO: Opened hardware target localhost:3121/xilinx_tcf/Digilent/210292AA7B77A on try 1.
INFO: Found xc7a100tcsg324-1 as part of xc7a100t_0.
INFO: Programming bitstream to device xc7a100t_0 on target localhost:3121/xilinx_tcf/Digilent/210292AA7B77A.
ERROR: [Labtools 27-3165] End of startup status: LOW
program_hw_devices: Time (s): cpu = 00:01:47 ; elapsed = 00:02:12 . Memory (MB): peak = 1370.105 ; gain = 0.000 ; free physical = 6105 ; free virtual = 9385
ERROR: [Common 17-39] 'program_hw_devices' failed due to earlier errors.

while executing
"program_hw_devices [current_hw_device]"
(file "swervolf_0.7.3_pgm.tcl" line 98)
Makefile:23: recipe for target 'pgm' failed
make: *** [pgm] Error 1
ERROR: Failed to run ::swervolf:0.7.3 : '['make', 'pgm']' exited with an error: 2

Start by reproducing the `make pgm` failure for `run --target=nexys_a7 --flag=cpu_el2 swervolf` and inspect `swervolf_0.7.3_pgm.tcl` at line 98, where `program_hw_devices` is called. Compare the EH1 and EL2 runs; done means the bitstream programs successfully and the `pgm` target completes without the Labtools startup error.

Written by the indexing model from the issue text.