Ok... I guess this is a new thing since there was some work done on REPL?
```
 glasgow run --prebuilt-at bitstreams/selftest.bin selftest loopback voltage pins-loop
I: g.device.hardware: device already has bitstream ID c55794d8e963aba26782ca1bf4db4ebd
I: g.cli: running handler for applet 'selftest'
I: g.applet.internal.selftest: running self-test mode loopback
I: g.applet.internal.selftest: running self-test mode voltage
I: g.applet.internal.selftest: running self-test mode pins-loop
I: g.applet.internal.selftest: self-test: PASS
E: g.applet.internal.selftest: This applet can only be used in REPL mode.
```
I refer to the "This applet can only be run in REPL mode." error.