Size of boot partition and initrd sizes

[Riccardo Mottola <riccardo.mottola@libero.it>]

Hello,

I am in the process of updating, including the latest kernel (which 
probably will not work, but who knows).

Originally, I reserved about half a gigabyte, which became effective 
473M for my boot parittion and up to now it has been plenty

/dev/sda1       473M  382M   68M  85% /boot

Now, every time I try to regenerate initrd,  initramfs-tools dies with 
not enough space.

So I checked here:
-rw-r--r-- 1 root root 169K Apr  1 12:48 /boot/config-5.12.0-rc5+
-rw-r--r-- 1 root root 163K Dec 17 06:31 /boot/config-5.9.0-5-sparc64-smp
lrwxrwxrwx 1 root root   31 May 19 00:15 /boot/initrd.img -> 
initrd.img-5.10.0-6-sparc64-smp
-rw-r--r-- 1 root root 316M Apr  1 13:20 /boot/initrd.img-5.12.0-rc5+
-rw-r--r-- 1 root root  22M Mar 11 21:14 
/boot/initrd.img-5.9.0-5-sparc64-smp
lrwxrwxrwx 1 root root   22 May 19 00:54 /boot/initrd.img.old -> 
initrd.img-5.12.0-rc5+
-rw-r--r-- 1 root root 3.3M Apr  1 12:48 /boot/System.map-5.12.0-rc5+
-rw-r--r-- 1 root root   83 Dec 17 06:31 
/boot/System.map-5.9.0-5-sparc64-smp
-rw-r--r-- 1 root root  13M Apr  1 15:34 /boot/vmlinux-5.12.0-rc5+
-rwxr-xr-x 1 root root  16M Dec 17 06:31 /boot/vmlinux-5.9.0-5-sparc64-smp
lrwxrwxrwx 1 root root   28 May 19 00:15 /boot/vmlinuz -> 
vmlinux-5.10.0-6-sparc64-smp
lrwxrwxrwx 1 root root   19 May 19 00:54 /boot/vmlinuz.old -> 
vmlinux-5.12.0-rc5+


I noticed that my old initrd.img was 22M... and the new one is 316M! 
since initramfs creates a back up copy, it does not find.

Why is it now more than 10 times lager? what makes up this size? I 
wonder if it is due to new kernel or does initramfs depend on selected 
packages...
What does get put in in in the ramfs, maybe something I can trim?

Thanks,
Riccardo