[Lenovo Legion Y700] randomy:
I tried again but got same result, below is output while fastboot flashing

maybe there are some issues on device while switching to rom version

1. md5sum was matched

2. as you mentioned, fastboot update set slot automatically

I have tried, fastboot --set-active=b but no luck

nnnlife@5900x:~$ fastboot oem device-info
(bootloader) Verity mode: false
(bootloader) Device unlocked: true
(bootloader) Device critical unlocked: true
(bootloader) Charger screen enabled: false
OKAY [ 0.000s]
Finished. Total time: 0.000s
nnnlife@5900x:~$ fastboot getvar current-slot
current-slot: b
Finished. Total time: 0.006s

fastboot update --skip-reboot aospa-uvite-unofficial-asphalt-20240317-image.zip
--------------------------------------------
Bootloader Version...:
Baseband Version.....:
Serial Number........: HA1XV3Q1
--------------------------------------------
extracting android-info.txt (0 MB) to RAM...
Checking 'product' OKAY [ 0.003s]
Setting current slot to 'b' OKAY [ 0.007s]
archive does not contain 'fastboot-info.txt'
extracting boot.img (96 MB) to disk... took 0.200s
archive does not contain 'init_boot.img'
extracting dtbo.img (23 MB) to disk... took 0.041s
archive does not contain 'dt.img'
archive does not contain 'pvmfw.img'
extracting recovery.img (100 MB) to disk... took 0.156s
extracting vbmeta.img (0 MB) to disk... took 0.000s
extracting vbmeta_system.img (0 MB) to disk... took 0.000s
archive does not contain 'vbmeta_vendor.img'
extracting vendor_boot.img (96 MB) to disk... took 0.131s
archive does not contain 'vendor_kernel_boot.img'
archive does not contain 'boot_other.img'
extracting odm.img (1 MB) to disk... took 0.012s
archive does not contain 'odm_dlkm.img'
extracting product.img (1581 MB) to disk... took 3.708s
extracting system.img (1030 MB) to disk... took 2.419s
archive does not contain 'system_dlkm.img'
extracting system_ext.img (506 MB) to disk... took 1.145s
archive does not contain 'system_other.img'
extracting vendor.img (816 MB) to disk... took 1.946s
extracting vendor_dlkm.img (116 MB) to disk... took 0.233s
archive does not contain 'vendor_other.img'
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting super_empty.img (0 MB) to RAM...
extracting boot.img (96 MB) to disk... took 0.200s
archive does not contain 'boot.sig'
extracting super_empty.img (0 MB) to RAM...
Sending 'boot_b' (98304 KB) OKAY [ 2.342s]
Writing 'boot_b' OKAY [ 0.169s]
extracting super_empty.img (0 MB) to RAM...
extracting dtbo.img (23 MB) to disk... took 0.041s
archive does not contain 'dtbo.sig'
extracting super_empty.img (0 MB) to RAM...
Sending 'dtbo' (24576 KB) OKAY [ 0.571s]
Writing 'dtbo' OKAY [ 0.035s]
extracting super_empty.img (0 MB) to RAM...
extracting recovery.img (100 MB) to disk... took 0.156s
archive does not contain 'recovery.sig'
extracting super_empty.img (0 MB) to RAM...
Sending 'recovery' (102400 KB) OKAY [ 2.394s]
Writing 'recovery' OKAY [ 0.151s]
extracting super_empty.img (0 MB) to RAM...
extracting vbmeta.img (0 MB) to disk... took 0.000s
archive does not contain 'vbmeta.sig'
extracting super_empty.img (0 MB) to RAM...
Sending 'vbmeta' (8 KB) OKAY [ 0.001s]
Writing 'vbmeta' OKAY [ 0.001s]
extracting super_empty.img (0 MB) to RAM...
extracting vbmeta_system.img (0 MB) to disk... took 0.000s
archive does not contain 'vbmeta_system.sig'
extracting super_empty.img (0 MB) to RAM...
Sending 'vbmeta_system' (4 KB) OKAY [ 0.001s]
Writing 'vbmeta_system' OKAY [ 0.001s]
extracting super_empty.img (0 MB) to RAM...
extracting vendor_boot.img (96 MB) to disk... took 0.132s
archive does not contain 'vendor_boot.sig'
extracting super_empty.img (0 MB) to RAM...
Sending 'vendor_boot' (98304 KB) OKAY [ 2.326s]
Writing 'vendor_boot' OKAY [ 0.156s]
extracting super_empty.img (0 MB) to disk... took 0.000s
Rebooting into fastboot OKAY [ 0.002s]
< waiting for any device >