The getvar indicated the issue. I was able to get back to Android this way:
Code:
C:\>fastbogus --set-active=b
Setting current slot to 'b' OKAY [ 0.048s]
Finished. Total time: 0.049s
C:\>fastbogus boot long.img
Sending 'boot.img' (98304 KB) OKAY [ 2.265s]
Booting OKAY [ 0.093s]
Finished. Total time: 2.414s
Maybe I should not try to root this device since my fastboot is broken.