With a manual or tutorial to hold my hand I can navigate grub just fine, but luckily it didn't come to that.
I tried mounting the USB stick to look for that file as you requested, but it didn't automount (strange), and when trying to mount manually:
sudo mount /dev/sdb1 /mnt -t vfat
it refused to mount, showing this in the log file:
FAT-fs (sdb1): invalid media value (0x63)
FAT-fs (sdb1): Can't find a valid FAT filesystem
To indirectly validate the presence of .disk/casper-uuid, I mounted the .iso image from Downloads/ as a loop device, and indeed, it's there.
I then tried to build boot media again, this time on a USB hard disk. This built fine and the file was there and everything, but for some reason the laptop refused to boot from this disk.
I started seriously suspecting the USB stick but as seen before, when an image is burned it works fine. So I suspected filesystem size. The only peculiarity about this USB stick is that it's 16GB, which sounds big for a VFAT filesystem. I manually built a 5-GB filesystem on the stick (using fdisk and mkfs.vfat) and just specified "make startup disk" while creating the boot media (not erasing it as before).
First off, this does automount when I plug it in, and I see .disk/casper-uuid there. Also, happily, the USB stick now boots the recovery utility without problems.
I guess the same problem that kept Ubuntu from recognizing the hard disk also caused grub to be unable to read the filesystem, and thus fail to find .disk/casper-uuid.
Looks like I'll have to get a 4- or 8-GB stick to keep my recovery backup.
I'd be OK with marking this bug as Invalid as it was due to the too-large USB stick, but I'll let you decide on the status, in case you want more information on what makes this stick fail so strangely.
This USB stick is a 16-GB ADATA USB 3.0 unit, here's the lsusb data:
Bus 002 Device 010: ID 125f:312b A-DATA Technology Co., Ltd. Superior S102 Pro
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x125f A-DATA Technology Co., Ltd.
idProduct 0x312b Superior S102 Pro
bcdDevice a.00
iManufacturer 1 ADATA
iProduct 2 ADATA USB Flash Drive
iSerial 3 0000000000000400
bNumConfigurations 1
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 32
bNumInterfaces 1
bConfigurationValue 1
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescriptorType 4
bInterfaceNumber 0
bAlternateSetting 0
bNumEndpoints 2
bInterfaceClass 8 Mass Storage
bInterfaceSubClass 6 SCSI
bInterfaceProtocol 80 Bulk-Only
iInterface 0
Endpoint Descriptor:
bLength 7 bDescriptorType 5 bEndpointAddress 0x02 EP 2 OUT bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Endpoint Descriptor:
bLength 7 bDescriptorType 5 bEndpointAddress 0x81 EP 1 IN bmAttributes 2
Transfer Type Bulk
Synch Type None
Usage Type Data wMaxPacketSize 0x0200 1x 512 bytes
bInterval 0
Device Status: 0x0000
(Bus Powered)
Hi Mario,
With a manual or tutorial to hold my hand I can navigate grub just fine, but luckily it didn't come to that.
I tried mounting the USB stick to look for that file as you requested, but it didn't automount (strange), and when trying to mount manually:
sudo mount /dev/sdb1 /mnt -t vfat
it refused to mount, showing this in the log file:
FAT-fs (sdb1): invalid media value (0x63)
FAT-fs (sdb1): Can't find a valid FAT filesystem
To indirectly validate the presence of .disk/casper-uuid, I mounted the .iso image from Downloads/ as a loop device, and indeed, it's there.
I then tried to build boot media again, this time on a USB hard disk. This built fine and the file was there and everything, but for some reason the laptop refused to boot from this disk.
I started seriously suspecting the USB stick but as seen before, when an image is burned it works fine. So I suspected filesystem size. The only peculiarity about this USB stick is that it's 16GB, which sounds big for a VFAT filesystem. I manually built a 5-GB filesystem on the stick (using fdisk and mkfs.vfat) and just specified "make startup disk" while creating the boot media (not erasing it as before).
First off, this does automount when I plug it in, and I see .disk/casper-uuid there. Also, happily, the USB stick now boots the recovery utility without problems.
I guess the same problem that kept Ubuntu from recognizing the hard disk also caused grub to be unable to read the filesystem, and thus fail to find .disk/casper-uuid.
Looks like I'll have to get a 4- or 8-GB stick to keep my recovery backup.
I'd be OK with marking this bug as Invalid as it was due to the too-large USB stick, but I'll let you decide on the status, in case you want more information on what makes this stick fail so strangely.
This USB stick is a 16-GB ADATA USB 3.0 unit, here's the lsusb data:
Bus 002 Device 010: ID 125f:312b A-DATA Technology Co., Ltd. Superior S102 Pro tions 1 ionValue 1 orType 4 eNumber 0 eSetting 0 eClass 8 Mass Storage eSubClass 6 SCSI eProtocol 80 Bulk-Only
bDescriptorTyp e 5
bEndpointAddre ss 0x02 EP 2 OUT
bmAttributes 2
wMaxPacketSize 0x0200 1x 512 bytes
bDescriptorTyp e 5
bEndpointAddre ss 0x81 EP 1 IN
bmAttributes 2
wMaxPacketSize 0x0200 1x 512 bytes
Device Descriptor:
bLength 18
bDescriptorType 1
bcdUSB 2.10
bDeviceClass 0 (Defined at Interface level)
bDeviceSubClass 0
bDeviceProtocol 0
bMaxPacketSize0 64
idVendor 0x125f A-DATA Technology Co., Ltd.
idProduct 0x312b Superior S102 Pro
bcdDevice a.00
iManufacturer 1 ADATA
iProduct 2 ADATA USB Flash Drive
iSerial 3 0000000000000400
bNumConfigura
Configuration Descriptor:
bLength 9
bDescriptorType 2
wTotalLength 32
bNumInterfaces 1
bConfigurat
iConfiguration 0
bmAttributes 0x80
(Bus Powered)
MaxPower 500mA
Interface Descriptor:
bLength 9
bDescript
bInterfac
bAlternat
bNumEndpoints 2
bInterfac
bInterfac
bInterfac
iInterface 0
Endpoint Descriptor:
bLength 7
Transfer Type Bulk
Synch Type None
Usage Type Data
bInterval 0
Endpoint Descriptor:
bLength 7
Transfer Type Bulk
Synch Type None
Usage Type Data
bInterval 0
Device Status: 0x0000
(Bus Powered)