bug#55405: Image API produces incorrect images

[Pavel Shlyak]

I have a scheme code like

(define rpi-boot-partition
(partition
(size (* 128 (expt 2 20)))
(label "BOOT")
(file-system "vfat")
(flags '())
(initializer (gexp initialize-efi-partition))))

(define rpi-root-partition
(partition
(size 'guess)
(label "RASPIROOT")
(file-system "ext4")
(flags '(boot))
(initializer (gexp initialize-root-partition))))

(define raspberry-pi-image
(image
(format 'disk-image)
(partitions (list rpi-boot-partition rpi-root-partition))))

The output is like that:
$ fdisk -l 
/gnu/store/hnsfs5a161f5hvymg7ar541qrml62yvv-raspberry-pi-barebones-raw-image
Device                                                                        
Boot  Start     End Sectors  Size Id Type
/gnu/store/hnsfs5a161f5hvymg7ar541qrml62yvv-raspberry-pi-barebones-raw-image1   
        1  262144  262144  128M 83 Linux
/gnu/store/hnsfs5a161f5hvymg7ar541qrml62yvv-raspberry-pi-barebones-raw-image2   
   262145 3583688 3321544  1.6G 83 Linux        

No boot flag is set on the first partition. The file system seems to be 
incorrect (ext* instead of vfat)