Bug#984488: I've met the same bug

[Dmitry Kondratyev]

Hello,

After upgrading grub from 2.02+dfsg1-20+deb10u3 to 2.02+dfsg1-20+deb10u4 
I've met the same bug on all boxes with MD raid1 partition starting from 
sector 63.

/boot/grub/i386-pc/core.img is 31120 bytes and should fit, but i get:

Installing for i386-pc platform.
grub-install: warning: your core.img is unusually large.  It won't fit 
in the embedding area.
grub-install: error: embedding is not possible, but this is required for 
RAID and LVM install.

Rolling back to 2.02+dfsg1-20+deb10u3 solves the problem and everything 
works with the same core.img (MD5 is the same).