Re: Question about aarch64 image

[mlelstv%serpens.de@localhost (Michael van Elst)]

john%klos.com@localhost (John Klos) writes:

>I'm wondering why might this be the case.

% gpt header 2024-11-24-netbsd-raspi-aarch64.img 
Media Size: 3139182592 (3G)
Sector Size: 512
Number of Sectors: 6131216 (6M)

Header Information:
- GPT Header Revision: 1.0
- First Data Sector: 3 (3B)
- Last Data Sector: 6131213 (6M)
- Media GUID: d5a704a7-2580-4880-9a63-4eb226edc0fa
- Number of GPT Entries: 2

For some reason, the GPT in that image is sized to have 2 possible
table entries. The default is 128 entries, so the layout looks like:

       start        size  index  contents
           0           1         PMBR
           1           1         Pri GPT header
           2          32         Pri GPT table
          34      206814      1  GPT part - EFI System
...
  3907028992         143         Unused
  3907029135          32         Sec GPT table
  3907029167           1         Sec GPT header


Each of the 32 GPT table blocks (512 bytes) can store 4 entries.
The first partition starts on block 34 and prevents extending
the table. The last partition may prevent extending the GPT copy.

The aarch64 image looks like:

    start     size  index  contents
        0        1         PMBR
        1        1         Pri GPT header
        2        1         Pri GPT table
        3    90200      1  GPT part - EFI System
    90203  6041010      2  GPT part - NetBSD FFSv1/FFSv2
  6131213        1         Unused
  6131214        1         Sec GPT table
  6131215        1         Sec GPT header

The one table block is good for 4 entries, so you could
patch the header to also allow 4 instead of 2, but there 
is no command to do that.